Trade corrections originating at an exchange floor

Imported from previous forum

Hi,
I have been looking at the possible scenarios when a trade correction occurs. There are two question I would like to seek assistance from all you FIX experts out there:

  1. If an order receives various partial fills until fully executed, and the execution(s) were reported in error (in part or in whole) - "Un-executed", FIX sends a Cancel Execution - does FIX send one report of Cancel Execution, or does FIX instead send Cancel Executions for each partial fill?
  2. If an order were Executed, and the Trader agrees to "bust" the order (Cancel out a valid Execution in order to cancel the trade) would FIX send a "Cancel Execution" and then a "Cancel" for the order, or would FIX only send a "Cancel"?
    thank you in advance,
    Amrit.