diff --git a/src/java/com/threerings/presents/server/ClientManager.java b/src/java/com/threerings/presents/server/ClientManager.java
index b6ce1672c..4460135d1 100644
--- a/src/java/com/threerings/presents/server/ClientManager.java
+++ b/src/java/com/threerings/presents/server/ClientManager.java
@@ -1,5 +1,5 @@
 //
-// $Id: ClientManager.java,v 1.21 2002/07/23 05:52:49 mdb Exp $
+// $Id: ClientManager.java,v 1.22 2002/09/16 23:34:25 mdb Exp $
 
 package com.threerings.presents.server;
 
@@ -185,6 +185,45 @@ public class ClientManager implements ConnectionObserver
         }
     }
 
+    /**
+     * Remaps a client from its old username to the specified new
+     * username. The client must end its session using the new username.
+     * This most likely shouldn't be called anywhere except from {@link
+     * PresentsClient#setUsername}.
+     *
+     * @return true if the remapping succeeded, false if it failed.
+     */
+    protected synchronized boolean remapClient (
+        String oldname, String newname)
+    {
+        // make sure they are already mapped
+        PresentsClient client = (PresentsClient)_usermap.remove(oldname);
+        if (client == null) {
+            Log.warning("Aiya! Can't remap non-existent user " +
+                        "[oldname=" + oldname + ", newname=" + newname + "].");
+            return false;
+        }
+
+        // map them under their new name
+        _usermap.put(newname, client);
+
+        // release their old lock and create a lock for their new name
+        releaseClient(oldname);
+        lockClient(newname);
+
+        // update their client object mapping
+        ClientObject clobj = (ClientObject)_objmap.remove(oldname);
+        if (clobj == null) {
+            Log.warning("Aiya! Unable to unmap old client object when " +
+                        "remapping user [oldname=" + oldname +
+                        ", newname=" + newname + "]. Hoping for the best.");
+        } else {
+            _objmap.put(newname, clobj);
+        }
+
+        return true;
+    }
+
     /**
      * When a client object becomes part of an active session, this method
      * should be called to ensure that it is not unloaded by any entities
diff --git a/src/java/com/threerings/presents/server/PresentsClient.java b/src/java/com/threerings/presents/server/PresentsClient.java
index 9c4b49cae..000ec9b42 100644
--- a/src/java/com/threerings/presents/server/PresentsClient.java
+++ b/src/java/com/threerings/presents/server/PresentsClient.java
@@ -1,5 +1,5 @@
 //
-// $Id: PresentsClient.java,v 1.35 2002/08/14 19:07:56 mdb Exp $
+// $Id: PresentsClient.java,v 1.36 2002/09/16 23:34:25 mdb Exp $
 
 package com.threerings.presents.server;
 
@@ -62,6 +62,36 @@ public class PresentsClient
         return _username;
     }
 
+    /**
+     * <em>Danger:</em> this method is not for general consumption. This
+     * changes the username of the client, but should only be done very
+     * early in a user's session, when you know that no one has mapped the
+     * user based on their username or has in any other way made use of
+     * their username in a way that will break. However, it should not be
+     * done <em>too</em> early in the session. The client must be fully
+     * resolved.
+     *
+     * <p> It exists to support systems wherein a user logs in with an
+     * account username and then chooses a "screen name" by which they
+     * will play (often from a small set of available "characters"
+     * available per account). This will take care of remapping the
+     * username to client object mappings that were made by the Presents
+     * services when the user logs on, but anything else that has had its
+     * grubby mits on the username will be left to its own devices, hence
+     * the care that must be exercised when using this method.
+     */
+    public void setUsername (String username)
+    {
+        // remap the client object in the client manager
+        if (_cmgr.remapClient(_username, username)) {
+            // change our internal business
+            _username = username;
+        } else {
+            Log.warning("Unable to remap username [client=" + this +
+                        ", newname=" + username + "].");
+        }
+    }
+
     /**
      * Returns the client object that is associated with this client.
      */