GitLab CE on-premise - Domain Migration

Hello all,

We have installed GitLab CE before 2 years ago on our old domain called old-domain.local
For security reasons, when moving offices before 1 year ago, we created a new domain called new-domain.local.

All our R&D users connect our R&D platforms with our new-domain.local LDAP authentication credentials except GitLab since GitLab using old-domain.local LDAP authentication.

All users logon name are similar between old-domain.local to new-domain.local. Is there a simple way/tool to migrate our GitLab users from old-domain.local to new-domain.local?