user_query: start a list of potential presents
response_text: Alright, what do you want to call it?
user_query: possible presents
response_text: OK, I made a list called "Possible Presents" and added potential presents.
user_query: Forget the potential presents
response_text: Sure, I deleted potential presents.
User: Buy 2, no make that 4, tickets on Ticketmaster, to see Adele's concert in Las Vegas.
Parse: BuyEventTickets ( event_location « Las Vegas » event_performer « Adele » event_type « concert » provider « Ticketmaster » ticket_quantity « 4 » )