function gogo()
if GetObjectiveState("quest name at the prophet") == OBJECTIVE_COMPLETED then
RemoveObject("Name of the object to be deleted")
end
end
Trigger(OBJECTIVE_STATE_TRIGGER, "quest name at the prophet", "gogo")
Some immediate comments:
1) The object to be deleted must be of type Static, and the IsRemovable property must be set to true (check in the objectPropretiesTree).
The name is, of course, given there as well – in the name field.
2) If the quest is the same for multiple players and for the same object, we insert a check for IsObjectExists. Then we delete it.
3) Strictly speaking, I haven't tested this trigger for prophet quests. But it most likely works.