If I complete campaign on Halo 3 and change my acc to Xbox Live will I have to complete it again?

I've almost completed legendary on Halo 3, and I was wondering if I changed it to a Xbox Live account will I have to complete it again or will it transfer over. Cause i'm buying gold in a couple of weeks.|||The answer is no. If you upgrade your account to gold it will not affect any saved data on the profile other than allowing you to play in matchmaking. Just don't make a new profile...|||It will stay if you keep the same acc and not make a new one|||if you stay on same account, then it will be there. if you change, then you have to start all over.|||Just stay on the same accoun and youll be all set i mad the bad mistake and beat half my games then got a diffrent account cuz the one i had couldent get live|||if you keep the same account and transfer it to xbox live and don't make a new one then it should stay.|||Basically you can have any online name you want as long as it's not taken, and on any offline account you have. You don't have to keep your offline name. Any achievements on the offline account will be on the respective online account, the account you choose to upgrade will keep all the achievements. Plus if your really stuck some people are always willing to help you on campaign.