Hi,
If the domain size is larger then you may face the problem while moving the account from one server to another server via WHM. In such case, you can try to move the account using SSH. Below are the few commands to move the accccount:
TO PACK ANY ACCOUNT:
/scripts/pkgacct nameoftheuser
TO MOVE ONE TAR FILE TO ANOTHER SERVER. IT REQUIRES SERVER ROOT PASSWORD:
scp /home/name_of_tar_file root@IP_DESTINY_SERVER:/home/ name_of_tar_file
Restoring Packed Account:
/scripts/restorepkg nameoftheuser
Thanks,