I want to deactivate following code of Codeunit 81 , as I want to ConfirmPost the sales , the dialog box showed just 'Ship'

Please let me know how can we see existing code of CU 81 using business central 365,
I try create an overloading function with the same name of procedure and with a subscriber event 'OnBeforeConfirmSalesPost' but it doesn't work when I publish the two functions run .
Thanks