You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My self Donna White.

ASSISTANT: Donna, how can I help you?

USER: I have planned to attend a seminar in Seattle SEA on 05/11, could you book a flight ticket for me?

ASSISTANT: Sure, I will help you with that. May I know  the nearest airport code and the return day to your city?

USER: I would like to return on 05/13 and my source region airport code is BOS.

ASSISTANT: Ok, please wait for a moment, I will check the details of the flight.

USER: Sure.

ASSISTANT: Thank you for waiting Donna.

USER: It's alright.

ASSISTANT: There are no flights found on your requirement. Do you have any other travelling dates?

USER: Ok, no problem, thanks for your valuable information. No, I did not planned yet.

ASSISTANT: Thank you, have a great day.

USER: Thank you.

ASSISTANT: You are welcome.