I heard there's a LOT of Enron logos in the park yet, including a stamp at the end of each row of seats... in an article on ESPN about a month ago they said that even if they were to announce it changed that day it would be too short notice to get Enron completely wiped from the stadium.
CK
EDIT: Not to say they can't change their name, but there would still be Enron markings around the field, is all I'm saying.