Dennis wants to change his Google ID into a nickname. Leo says it's not possible to do it natively. There are some "name shorteners" that will let him do it, but it's far easier to just use a URL shortener like Bit.Ly. He should get his Google Plus link, copy it, and then go to Bit.Ly. He can input the link, give it his nickname, and that's it. Then he can give people that link.
There is another URL shortener designed to be used more with Google+: gplus.to.