When upgrading to Helpdesk version 7.3 you need to ensure you have disabled the following triggers on your database.
D_CALL and D_UPDMON
These triggers were put in place to ensure that the control points were changed on a calls when the SLA was changed.
7.3 has fixed this issue so the triggers are no longer needed.
These triggers are found on the CALL_HDW and UPDMON_HDW tables.