Delete the old LDAP user federation and create a new one. This procedure should only be done if the LDAP server is being replaced by a different LDAP server that has different contents.
Refer to Change the LDAP Server IP Address for Existing LDAP Server Content if the new LDAP server content matches the previous LDAP server content.
The LDAP server is being replaced by a different LDAP server that has different contents. For example, different users and groups.
Remove the LDAP user federation from Keycloak.
Follow the procedure in Remove the LDAP User Federation from Keycloak.
Re-add the LDAP user federation in Keycloak.
Follow the procedure in Add LDAP User Federation.