post https://api.signeasy.com/v3/rs/embedded//cancel/
The API is used to cancel the signers of an individual pending file by using the pending_file_id.
The API also sends cancellations emails and a callback event (rs.cancelled) with data to a predefined URL endpoint configured using the callbacks API.
The pending_file_id is passed as a query parameter to the redirect url in the Fetch RS sending URL request.