I filed return under nickname. Do I need to do an amended return?

I filed a return for a friend of mine, and I did not realize until after the returned was filed and I printed out the copy that I had used my friends nickname of Kasey instead of her given name of Kristen.  Will I have to file an amended return, or should I wait until the IRS or State rejects the return due to the wrong name?  All the other information is correct on the return.