An important problem in designing infrastructure to support business-to-business integration (B2Bi) is how to cancel a long-running interaction (either because the user has changed their mind, or in response to an unrecoverable failure). We review the fault-handling and compensation mechanism that is now used in most workflow products and business process modeling standards. We then use an e-procurement case-study to extract a set of requirements for an effective cancellation mechanism, and we show that the standard approach using fault-handling, and compensation transactions is not adequate to meet these requirements.