diff --git a/src/java/com/threerings/presents/server/ClientManager.java b/src/java/com/threerings/presents/server/ClientManager.java
index 58c42ec2b..335ed6712 100644
--- a/src/java/com/threerings/presents/server/ClientManager.java
+++ b/src/java/com/threerings/presents/server/ClientManager.java
@@ -24,7 +24,6 @@ package com.threerings.presents.server;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.logging.Level;
 
@@ -307,6 +306,23 @@ public class ClientManager
         PresentsServer.omgr.destroyObject(clobj.getOid());
     }
 
+    /**
+     * Renames a currently connected client from <code>oldname</code> to <code>newname</code>
+     * 
+     * @return true if the client was found and renamed.
+     */
+    protected boolean renameClientObject (Name oldname, Name newname)
+    {
+        ClientObject clobj = _objmap.remove(oldname);
+        if (clobj == null) {
+            log.warning("Requested to rename unmapped client object [username=" + oldname + "].");
+            Thread.dumpStack();
+            return false;
+        }
+        _objmap.put(newname, clobj);
+        return true;
+    }
+
     // documentation inherited from interface ClientResolutionListener
     public synchronized void clientResolved (Name username, ClientObject clobj)
     {
diff --git a/src/java/com/threerings/presents/server/PresentsClient.java b/src/java/com/threerings/presents/server/PresentsClient.java
index cebd42b67..dcec78ddb 100644
--- a/src/java/com/threerings/presents/server/PresentsClient.java
+++ b/src/java/com/threerings/presents/server/PresentsClient.java
@@ -261,6 +261,24 @@ public class PresentsClient
         _cmgr.resolveClientObject(username, clr);
     }
 
+    /**
+     * <em>Double Danger:</em> this method is not for general consumption. Like
+     * {@code #setUsername}, this changes the username of the client, but unlike setUsername, it
+     * does it in the existing client object. Care must be taken to ensure that any client or
+     * server code either doesn't map things based on username before this call, or that it's
+     * updated to reflect the change.
+     * 
+     * @return - true if the client was successfully renamed, false otherwise
+     */
+    public boolean updateUsername (Name username)
+    {
+        if (_cmgr.renameClientObject(_username, username)) {
+            _username = username;
+            return true;
+        }
+        return false;
+    }
+
     /**
      * Returns the client object that is associated with this client.
      */