How can I change the address of a mail account on the linux server without missing the mailbox content? I want to change an existing address from name1@domain.com to name2@domain.com for a client wanting to keep all old messages.
(No matter if I can use WHM or SSH)

Following this method...

. Create name2@domain.com
. Move all files from /home/UID/mail/domain.com/name1 to -->> /home/UID/mail/domain.com/name2

It should work.

* UID ==> User Login ID