How can i change the name of the project after i'v already made some work into it

I’v tried to change the name of the file and the DefaultEngine.ini file to have the same name in there but when i try to enter it it enters into the scene and then crush back to desktop and gives me some error message .

changing the game name in the DefaultEngine.ini in the config folder and renaming the Unreal Engine Project File to the same name worked for me all the time thus far. What kind of error message did you get?

Well, it crushed once, and then worked for good, hope it stays good :S Thanks though.