If you're asking for a fee waiver, you need to do so before your app is submitted. As far as I know, schools don't refund any application fees you have already paid. I would email whatever school you're applying to and ask if they waive the CAS fee.
... the test date change and refund deadlines have passed, you find ... you will not receive a refund. (If you register for another ... be automatically withdrawn, without a refund"