You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What kind of services are you looking from us?

USER: I am Mark Davis. I am planning to visit Boston BOS from IAD. Can you find a flight ticket for me?

ASSISTANT: Mark Davis, can you please mention your travel dates?

USER: Sure, I am planning to travel on these days that is on Mar 19 and return on  Mar 21.

ASSISTANT: Do you have any airlines preference?

USER: Yes, I need a single connecting flight.

ASSISTANT: Are you looking any airline preference?

USER: No, I don't have any specifications.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry for inconvenience, no flights are found with your criteria.

USER: Ok, not an problem.

ASSISTANT: Thank you very much for approaching us.

USER: Thank you for your information.