On the InterMiles website or App, you can request for cancellation of the bookings done on our platform. In order to do so, you must enter your credentials on this link. Once done, you can select the booking you intend to cancel and click on Cancel/Claim Refund button. The refund will be processed to you within 7-10 days and will reflect in the account that was charged.
For any date change request of any flight bookings you can directly reach out to the airlines concerned. In case of credit shell info- look it up here