That is an invalid WikiTree ID, which is why it won't let you do that. If you attempt to bring up a profile with that exact WikiTree ID, it comes up as good old error 404.
Look closer where you have referenced that person previously (probably in G2G), follow their name through the link and you'll probably see that there's a different character for the apostrophe where WikiTree is probably using one of the ASCII characters (usually something like %39) or it's spelled slightly differently.
If you can point out where you saw this originally, I might be able to trace it for you.