user_query: add socks to shopping list
response_text: OK, I added socks.
user_query: scratch that add handkerchief instead 
response_text: Sure, I changed the list item to handkerchief on your list called "shopping."
user_query: shopping list
response_text: You have three things on that list.
User: Please call Stacy at home.
Parse: Initiate_call ( callee Personal_contact ( label « home » person « Stacy » ) )