find all Files from old User chown to new User

find /$PATH -user $OLDUSER -exec chown $NEWUSER {} \;

User simple Mailforward

User Home  .forward

to forward user address without root privileges, just create the file .forward in the home directory with inside the name of the mail address:

[user@localhost ~]$ pwd
[user@localhost ~]$ echo "" > .forward
[user@localhost ~]$ chmod 644 .forward
[user@localhost ~]$

every mail to user@localhost will be forwarded to without leaving a copy on the server.