Can you cancel a re-enlistment?

I just re-enlisted last month and I re-enlisted to convert to corpsman because my rate now is currently over manned. I just found out last week that my school was denied and I also found out that I was chosen for Bahrain IA orders... Since I re-enlisted to cross rate and I was denied does that mean my re-enlistment can be canceled since that is what is was intended for?