The Access database should have returned a repeating node-set. Whether there are attributes involved should be irrelevant because it is the elements that you want to remove.
You are on the right track, it sounds like you are just attempting to remove the incorrect node. If you are trying to remove an attribute now, maybe all you need to do is move up to the attribute's parent element and remove that. Just make sure you are removing the repeating node itself, not one of its descendant nodes.
As for inserting, you need to get a copy of that same repeating node, fill in or clear values as appropriate, and then insert it into the appropriate place using appendChild or insertBefore.