how to non-destructively alter partitions

I have two partitions on my drive, one of them is currently empty, and i want to join them as one partition so that I can run bootcamp. I definately don't want to back up everything and format my harddrive. Can anyone give advice on how to do this??

I am confused. Boot camp requires 2 partitions. 1 for osx and 1 for windows. But if you need to you may be able to run boot camp assistant there is an option to restore the drive to one partition. I am new to the apple world but I think that should work.