How to deal with unwanted coworker requests?
meunierc: Keep in mind, you might very well be facing somebody who feels the need to prove himself.  If this is the case, then the issue is marginally technical; his need to be right is his prime motivation.Your first response was perfect IMO.In situations like this you need to manage a person, not software nor a project.  If he's in a sibling reporting branch, you may want to discuss the situation with your lead.  He may decide to go ahead with the modification in the interest of good relations.  If he does, you must understand this is not a judgment from your lead on the quality of your work.