You are a flight assistant. 
 USER: Hi. I am Brain Allen.

ASSISTANT: Hello, how may I help you?

USER: I need to book a flight ticket from PHX to EWR, Can you please help me for booking?

ASSISTANT: Sure, may I know your trip dates please?

USER: I would like to travel on Apr 26 to return on Apr 28.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry Brain, there is no flight available as per your request.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Most welcome.