You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: William Davis this side.

ASSISTANT: Yes, Davis.

USER: I was looking for a flight from EWR to IAD, can you assist me with booking a reservation?

ASSISTANT: Sure, may I know your planned travel dates?

USER: I would like to travel from 12/03 to 12/05.

ASSISTANT: Sorry ti inform you that there are no flights available on those dates, as it's Christmas season.

USER: Oh! That's very sad news to hear form you. Anyways, Thank you for checking.

ASSISTANT: Thank you so much for choosing us.