Highh school classes?

My friend and i want the same classes together, we have one class. For her 1st period she has culaniry arts and her 6th period she has biolgy. For my 1st i have biolgy and 6th i have culaniry art. We want to swap it to were we have the same classes such as 1st period culaniry arts and 6th biolgy. I need an excuse to switch to her classes, and they wont let us if we say because our friend is in that class....Someone help? I reallly need to be in a class with my best friend its hard not having one. Thanks alot (: