Changing the assigning authority

A mistake happened and records were assigned the wrong assigning authority name: PID3.4.

Everything else  was correct. This resulted in duplicate records. Ex

Record 1: MRN1 has AA1 and clinical data

Record 2:  MRN1 has AA2 and the same clinical data as Record 1 + more clinical data that is not in Record 1

I would like to remove Record 2 ensuring that there are no orphan records left.

Should I use a merge transaction? If so, which one? The ones that I have seen expect a different MRN in the MRG segment. These records have the same MRN. What would be the best approach?

Thank you for reading!