[Mailman-Users] Changing a user's email address

If you have command line access, use bin/clone_member.

If not, this is an as yet unimplemented feature request. The only way
to currently do it as a list admin is to add the new address, set all
its member options the same as the old address and remove the old
address, but this changes the member's password so it isn't completely
satisfactory.