The alias is pulled over from AD - Unity does not manage the alias on its own and wont let you change it from our side. Strictly speaking we don't really care about the alias in most cases. We have a GUID that we find the user's AD/mailbox with and if items change in the directory, including the user's alias, it should eventually synch over to Unity's SQL DB which is what shows up in the SA.
So - what happened? did the alias get changed in AD and not sync over? Are there problems with this account from the Unity voice mail side of the fence?
