You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me with booking a flight ticket from IAH to EWR?

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

USER: My trip dates are Mar 14 and 16.

ASSISTANT: Do you have any other requirements?

USER: I would like to return at morning and prefer to travel in normal cost airlines.

ASSISTANT: Ok, can I know your name please?

USER: My name is Donald Walker.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: Ok, no issues. Thank you.

ASSISTANT: My pleasure.