Temporary slots in rasa?

Hi, is there a way to temporarily create a slot and then delete the slot once it isn’t needed? For example, I want to add a fetch-weather option in my bot, so I defined this action for that:

class Weather(Action):
def name(self):
    return "action_fetch_weather"
def run(self, dispatcher, tracker, domain):
    city = tracker.get_slot(ask_weather_in_city)

so this slot isn’t needed after rasa tells the weather. Can I make temporary slots, or is there a way to dynamically parse a part of the user message to get the city? How do I do that?

Why does the slot have to be temporary? Thinking that the user might as about the weather in a different city. Just for fun. So why not be able to handle these type of questions? Is it due to memory space on the server? Also thinking having it non temporary would generate more readable code.

Interesting thought though.