You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Please help me to book a flight ticket from SEA to IAD.

ASSISTANT: Sure, can I know your travelling dates?

USER: My travelling dates are from Apr, 21 to Apr, 23.

ASSISTANT: On which name should I reserve the flight ticket?

USER: Gregory Mitchell.

ASSISTANT: Do you have any connection limit?

USER: I do not have any specifications.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: Sorry, there are no flights found on given dates.

USER: Thank you for your information.

ASSISTANT: Thank you for reaching us.