How do I cancel financial aid at my current college ?

[The Truth Hurts !]

I plan on transferring back to my old college next semester, and the financial aid office at my old college said financial aid at my current school needs to be canceled before they can process aid at my old college I want to go to. How do I go about canceling it ?

P.S. I had an award letter for the 2010-2011 school at my old college but I told them I I was transferring to another college.