In ServiceDesk anywhere you will not see the concept or scope of deletion from Admin interface as many tables having dependent relation with other tables, which may cause serious data constraint issue in a running environment. So you have to technically deactivate the site defined condition as follows :
However if you want to really delete a record (obviously that's not advisable), you can delete the record from table Spell_Macro with pdm_load -r -f <File Name> command, however it may throw some database restriction and will be a complex process to achieve.
Thanks
ArunavaS