Did you know that if you do this the MG credit is forever and always still linked to the oringinal person who you accidentally paid that MG Pledge.
Found this out today after some testing. Apparently the only way to correct such an error is to delete and re-enter. Although you can change which pledge the gift is applied to - it pays the right pledge but does not change the donor credit in reports when you want to report Matching Gifts to the donor (or both).
Of course, I have used RE for 12 years and been to training and read RE manuals and never saw such instruction. Don't think this is documented as a KB solution either.