One of our registered MLOs transferred to a new position within the bank where he will no longer serve as an MLO in any way. Are we required to notify the Registry that he is no longer serving as an MLO? Or do we just not renew him at the next renewal period?

Just don't renew them. That number is like a SSA number. It will remain with them for their career. If they ever transfer to another FI or again become a MLO, they will use that same number.

Thank you!!