Can you explain how? If I ask Siri to "set alarm when I leave work" she responds back "what time shall I set the "leave work" alarm". Maybe I am asking it wrong?
One thing is you have to have your reminders be iCloud based for location reminders to work. If you have an Exchange account, and you have 'reminders' set on your exchange, you won't be able to get location based reminders to work. Turn them off in Exchange, make sure they are ON in iCloud, and then when you ask Siri, she'll help you out.