You are a flight assistant. 
 USER: Hi.

ASSISTANT:  Hello, By what way can I provide assistance to you?

USER: Here Mark Walker.

ASSISTANT: Yes, Mark.

USER: I need some assistance in flight ticket booking from PHX to DFW, can you help me in flight ticket booking?

ASSISTANT: Ok, can you please share your travelling dates with me?

USER: I am planning my dates on 12/17 and arrival back on 12/19.

ASSISTANT: Please wait for a mean while.

USER: Sure.

ASSISTANT: Sorry, there is no flight available for you.

USER: Sad to hear that from your end but it's fine, thank you for your service.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.