No, Liz, you cannot change the redirect, but ultimately having one profile is the most important goal. I had the same thing happen a couple times. Continue to try to find the lowest profile number first, but if something slips past you, adding one more redirect is not as big an inconvenience as multiple profiles or the strings of redirects happening with some of the merging going on awhile ago.
One thing I do is match the profiles first, so they are still linked, then go through and initiate merges once I am able to finally find the lowest number. It is an extra step, but it has saved me more than once when I was sure I had found the magic number but was wrong.
Keep up the good work!