delete
https://sandbox.dmhisp.com/SecureMessagingApi/Message/
This method is used to delete a message from a folder. When a message is deleted, it's normally moved to a Trash folder and then a Deleted Trash folder before being permanently purged from the DataMotion account. The trash deletion mechanism is controlled by the DataMotion server. Deleting a message only removes the message from the current user's account. It does not remove the message from the account of any other DataMotion users referenced in the message.