You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I guide you?

USER: I would like to go Philadelphia to attend a seminar, can you book a flight ticket from HOU to PHL?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: Ok, I want to go on 06/21 and back on 06/23.

ASSISTANT: May I know your good name please?

USER: My name is Dennis Walker.

ASSISTANT: Sorry, there is no flight available on your requested dates from HOU to PHL.

USER: Ok, no problem. Thank you for helping me.

ASSISTANT: Thank you for contacting us.