You're not able to cancel a client's orders directly. Whether to stop or continue a prescription is a medical decision, and that decision rests with the clinician and the client. For safety, the clinical team also won't abruptly halt someone's active treatment, since continuing or tapering a medication appropriately is part of caring for the client.
That said, you have a couple of options depending on how your program works:
A) If membership in your program is required to access your offerings through Altro, the client should first cancel their prescriptions through Altro. Once they've cancelled, they'll no longer receive new orders through the platform, and you're then free to cancel their membership with you.
B) Alternatively, you can let the client keep their Altro access even after they leave your program. Some partners prefer this, since you continue to earn on their Altro orders even once they're no longer in your coaching program.