You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you right now?

USER: Mark Phillips here.

ASSISTANT: Nice to meet you Mark.

USER: Please help me out in booking the ticket from HOU to PHX.

ASSISTANT: I understand your request and will be happy to help you. Certainly, may I know on what dates you need booking?

USER: Sure, my trip dates will be 10/07 and 10/09.

ASSISTANT: Sorry, all flight tickets are sold out on your requested travelling dates.

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thank you for consulting us. If any questions arise, please feel free to contact us at any time.