Jerry, you know the answer to that. A photocopy of course. If they agree, in writing, to replace the check then they would probably want the original back at which time you can provide it to them...
If it was an overpayment they would have stopped payment eventually. Unless you know for sure that it was, I would go ahead and try to get a new one issued. Tell them you put it away and just forgot
Wow Jerry, you must be a wealthy guy. Hold that check for 6 years and now thinking you won't even bother to see if you can get it paid? The advice of the Credit Union is of course what you should do.
Maria: I don't understand why it is important to you that the original report be amended to mention the fracture. Since it was discovered eventually, the record is clear what your injury was. I thought