Hey,
my first intuition would be to create an extra intent let’s say change_slot and two additional slots, which contain the name of the slot you want to change changing_slot_name and the value changing_slot_value.
Then you add a custom actions which is triggered when your intent is recognized and tries to set the slot with changing_slot_name to changing_slot_value.
Your stories would then look something like this (taken from the example stories in the docs):
...
* request_restaurant
- action_restaurant_form
- slot{"requested_slot": "people"}
* inform{"number": 3}
- action_restaurant_form
- slot{"people": 3}
- slot{"requested_slot": "cuisine"}
* change_slot{"changing_slot_name": "people", "chaning_slot_value": 5}
- action_change_slot
- slot{"people": 5}
...
I’m by no means an expert, so this might not be helpful at all.
Also I don’t think there is a build-in function for “re-asking” for FormActions, the only thing you could do is use the validate() function of FormFields to atleast catch “false” entries.