diff --git a/src/client/connect.rs b/src/client/connect.rs
index fdcc84a530..d347426e3c 100644
--- a/src/client/connect.rs
+++ b/src/client/connect.rs
@@ -6,9 +6,11 @@
 //!   establishes connections over TCP.
 //! - The [`Connect`](Connect) trait and related types to build custom connectors.
 use std::error::Error as StdError;
+use std::mem;
 
+use bytes::{BufMut, BytesMut};
 use futures::Future;
-use http::Uri;
+use http::{uri, Uri};
 use tokio_io::{AsyncRead, AsyncWrite};
 
 #[cfg(feature = "runtime")] pub use self::http::HttpConnector;
@@ -79,6 +81,144 @@ impl Destination {
         self.uri.port()
     }
 
+    /// Update the scheme of this destination.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use hyper::client::connect::Destination;
+    /// # fn with_dst(mut dst: Destination) {
+    /// // let mut dst = some_destination...
+    /// // Change from "http://"...
+    /// assert_eq!(dst.scheme(), "http");
+    ///
+    /// // to "ws://"...
+    /// dst.set_scheme("ws");
+    /// assert_eq!(dst.scheme(), "ws");
+    /// # }
+    /// ```
+    ///
+    /// # Error
+    ///
+    /// Returns an error if the string is not a valid scheme.
+    pub fn set_scheme(&mut self, scheme: &str) -> ::Result<()> {
+        let scheme = scheme.parse().map_err(::error::Parse::from)?;
+        self.update_uri(move |parts| {
+            parts.scheme = Some(scheme);
+        })
+    }
+
+    /// Update the host of this destination.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use hyper::client::connect::Destination;
+    /// # fn with_dst(mut dst: Destination) {
+    /// // let mut dst = some_destination...
+    /// // Change from "hyper.rs"...
+    /// assert_eq!(dst.host(), "hyper.rs");
+    ///
+    /// // to "some.proxy"...
+    /// dst.set_host("some.proxy");
+    /// assert_eq!(dst.host(), "some.proxy");
+    /// # }
+    /// ```
+    ///
+    /// # Error
+    ///
+    /// Returns an error if the string is not a valid hostname.
+    pub fn set_host(&mut self, host: &str) -> ::Result<()> {
+        if host.contains(&['@',':'][..]) {
+            return Err(::error::Parse::Uri.into());
+        }
+        let auth = if let Some(port) = self.port() {
+            format!("{}:{}", host, port).parse().map_err(::error::Parse::from)?
+        } else {
+            host.parse().map_err(::error::Parse::from)?
+        };
+        self.update_uri(move |parts| {
+            parts.authority = Some(auth);
+        })
+    }
+
+    /// Update the port of this destination.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use hyper::client::connect::Destination;
+    /// # fn with_dst(mut dst: Destination) {
+    /// // let mut dst = some_destination...
+    /// // Change from "None"...
+    /// assert_eq!(dst.port(), None);
+    ///
+    /// // to "4321"...
+    /// dst.set_port(4321);
+    /// assert_eq!(dst.port(), Some(4321));
+    ///
+    /// // Or remove the port...
+    /// dst.set_port(None);
+    /// assert_eq!(dst.port(), None);
+    /// # }
+    /// ```
+    pub fn set_port<P>(&mut self, port: P)
+    where
+        P: Into<Option<u16>>,
+    {
+        self.set_port_opt(port.into());
+    }
+
+    fn set_port_opt(&mut self, port: Option<u16>) {
+        use std::fmt::Write;
+
+        let auth = if let Some(port) = port {
+            let host = self.host();
+            // Need space to copy the hostname, plus ':',
+            // plus max 5 port digits...
+            let cap = host.len() + 1 + 5;
+            let mut buf = BytesMut::with_capacity(cap);
+            buf.put_slice(host.as_bytes());
+            buf.put_u8(b':');
+            write!(buf, "{}", port)
+                .expect("should have space for 5 digits");
+
+            uri::Authority::from_shared(buf.freeze())
+                .expect("valid host + :port should be valid authority")
+        } else {
+            self.host().parse()
+                .expect("valid host without port should be valid authority")
+        };
+
+        self.update_uri(move |parts| {
+            parts.authority = Some(auth);
+        })
+            .expect("valid uri should be valid with port");
+    }
+
+    fn update_uri<F>(&mut self, f: F) -> ::Result<()>
+    where
+        F: FnOnce(&mut uri::Parts)
+    {
+        // Need to store a default Uri while we modify the current one...
+        let old_uri = mem::replace(&mut self.uri, Uri::default());
+        // However, mutate a clone, so we can revert if there's an error...
+        let mut parts: uri::Parts = old_uri.clone().into();
+
+        f(&mut parts);
+
+        match Uri::from_parts(parts) {
+            Ok(uri) => {
+                self.uri = uri;
+                Ok(())
+            },
+            Err(err) => {
+                self.uri = old_uri;
+                Err(::error::Parse::from(err).into())
+            },
+        }
+    }
+
     /*
     /// Returns whether this connection must negotiate HTTP/2 via ALPN.
     pub fn must_h2(&self) -> bool {
@@ -121,6 +261,121 @@ impl Connected {
     */
 }
 
+#[cfg(test)]
+mod tests {
+    use super::Destination;
+
+    #[test]
+    fn test_destination_set_scheme() {
+        let mut dst = Destination {
+            uri: "http://hyper.rs".parse().expect("initial parse"),
+        };
+
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+
+        dst.set_scheme("https").expect("set https");
+        assert_eq!(dst.scheme(), "https");
+        assert_eq!(dst.host(), "hyper.rs");
+
+        dst.set_scheme("<im not a scheme//?>").unwrap_err();
+        assert_eq!(dst.scheme(), "https", "error doesn't modify dst");
+        assert_eq!(dst.host(), "hyper.rs", "error doesn't modify dst");
+    }
+
+    #[test]
+    fn test_destination_set_host() {
+        let mut dst = Destination {
+            uri: "http://hyper.rs".parse().expect("initial parse"),
+        };
+
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), None);
+
+        dst.set_host("seanmonstar.com").expect("set https");
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "seanmonstar.com");
+        assert_eq!(dst.port(), None);
+
+        dst.set_host("/im-not a host! >:)").unwrap_err();
+        assert_eq!(dst.scheme(), "http", "error doesn't modify dst");
+        assert_eq!(dst.host(), "seanmonstar.com", "error doesn't modify dst");
+        assert_eq!(dst.port(), None, "error doesn't modify dst");
+
+        // Also test that an exist port is set correctly.
+        let mut dst = Destination {
+            uri: "http://hyper.rs:8080".parse().expect("initial parse 2"),
+        };
+
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), Some(8080));
+
+        dst.set_host("seanmonstar.com").expect("set host");
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "seanmonstar.com");
+        assert_eq!(dst.port(), Some(8080));
+
+        dst.set_host("/im-not a host! >:)").unwrap_err();
+        assert_eq!(dst.scheme(), "http", "error doesn't modify dst");
+        assert_eq!(dst.host(), "seanmonstar.com", "error doesn't modify dst");
+        assert_eq!(dst.port(), Some(8080), "error doesn't modify dst");
+
+        // Check port isn't snuck into `set_host`.
+        dst.set_host("seanmonstar.com:3030").expect_err("set_host sneaky port");
+        assert_eq!(dst.scheme(), "http", "error doesn't modify dst");
+        assert_eq!(dst.host(), "seanmonstar.com", "error doesn't modify dst");
+        assert_eq!(dst.port(), Some(8080), "error doesn't modify dst");
+
+        // Check userinfo isn't snuck into `set_host`.
+        dst.set_host("sean@nope").expect_err("set_host sneaky userinfo");
+        assert_eq!(dst.scheme(), "http", "error doesn't modify dst");
+        assert_eq!(dst.host(), "seanmonstar.com", "error doesn't modify dst");
+        assert_eq!(dst.port(), Some(8080), "error doesn't modify dst");
+    }
+
+    #[test]
+    fn test_destination_set_port() {
+        let mut dst = Destination {
+            uri: "http://hyper.rs".parse().expect("initial parse"),
+        };
+
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), None);
+
+        dst.set_port(None);
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), None);
+
+        dst.set_port(8080);
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), Some(8080));
+
+        // Also test that an exist port is set correctly.
+        let mut dst = Destination {
+            uri: "http://hyper.rs:8080".parse().expect("initial parse 2"),
+        };
+
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), Some(8080));
+
+        dst.set_port(3030);
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), Some(3030));
+
+        dst.set_port(None);
+        assert_eq!(dst.scheme(), "http");
+        assert_eq!(dst.host(), "hyper.rs");
+        assert_eq!(dst.port(), None);
+    }
+}
+
 #[cfg(feature = "runtime")]
 mod http {
     use super::*;
diff --git a/src/error.rs b/src/error.rs
index 337bea0c5b..45feec53d7 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -350,6 +350,12 @@ impl From<http::uri::InvalidUri> for Parse {
     }
 }
 
+impl From<http::uri::InvalidUriParts> for Parse {
+    fn from(_: http::uri::InvalidUriParts) -> Parse {
+        Parse::Uri
+    }
+}
+
 #[doc(hidden)]
 trait AssertSendSync: Send + Sync + 'static {}
 #[doc(hidden)]