user_query: is tinsel on the Christmas list?
response_text: You have one thing on that list.
user_query: Put tinsel on 
response_text: OK, I added tinsel.
user_query: Changed my mind, delete tinsel
response_text: What do you want to call it instead?
User: Show me the food delivery apps.
Parse: Open_app ( app_category « food delivery » app_phrase « apps » )