You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name?

USER: My name is Thomas Miller.

ASSISTANT: Thomas, how may I help you?

USER: I am planning to visit my parents, so can you book a ticket for me? I am travelling from HOU to ATL.

ASSISTANT: Sure, may I know your travelling dates?

USER: My travel dates are 10/20 and 10/22.

ASSISTANT: I am sorry there is no flight available with your provided dates.

USER: No problem. Thank you for assisting me.

ASSISTANT: My pleasure.