If an administrator is asked to set or change permissions for a user, the easiest and best thing to do is set up a user with mbox admin permissions. This could be (but doesn't need to be) sxadmin. at a command line, type "ommodu sxadmin -c +mboxadmin". That will allow you to sign in as any other user on the system using the UID/PWD formatting shown in this thread. viewtopic.php?t=1596
This gives an admin the simplicity to do what seems to be requested, without knowing the user's password.
Kev.