no there is currently no method to remove a already stored alarm (apart from configuring a maximum number of recorded alarms).
You mind sharing why you would need such a method?
I have same suggestion and I can tell about some cases:
1. System goes over from test period to common work mode, so "test" information should be removed and it's not always possible to reload project.
2. New conditions are introduced (new workmode, new recipes, etc.) - so there is no longer any need for the "old" alarm history.
This feature also will be helpful for Trend element.