Hello Kristine ... very good question. My answer: Of course you can. Last I heard, you can do anything you want! But I do believe that some things have to be considered when you do change a traditional melody. For example, if you are going to record, or publish your 'new' version, you might consider noting the change. You might also explain why you chose to make the change. Other thoughts: there really is no "RIGHT WAY." This is a big wonderful world. I suspect that for every change you have made, many other singers have done just the same, many times, over the years. We just don't know about them. I expect that my good friend Don Firth will post soon and echo my thoughts. And, I also suspect he will mention that what you are doing is legimatly referred to as "the folk process." CHEERS and best wishes. Bob(deckman)Nelson