How do I cancel a stay without the client being charged and no penalties for either party?

A client double booked and I accepted both. I will be working with her, but she should not be charged for both requests. I read that if I cancel this close to the stay, my account will be suspended. If she cancels one, this close to the stay, she will be charged a cancelation fee. Again, I am not canceling my services, I want to cancel a double booking on the website so she is charged appropriately.