In relation to WFIs for IB, regardless of any entitlement to have them cancelled, the decision maker has discretion to cancel them for any claimant. (This is not the same as for ESA.)
Due to limitations/disabilities caused by medical conditions, a disabled person can make a request for "Reasonable Adjustments",to be made, with regards to any DWP, ATOS, Works Programme Providers requests, as they are all service providers.