You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Charles Scott.

ASSISTANT: Yes, Scott.

USER: I have to attend my sister's wedding at PHL, could you please help me with booking a flight ticket from DCA?

ASSISTANT: Sure, may I have your destination airport code? As you have already given that, may I have your planned dates for travelling?

USER: I would like to take off on 07/23 and return on 07/25.

ASSISTANT: Fine, wait a while. I will get back to you later.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no availability of flights on those dates.

USER: That's ok, I will find an another alternate way to complete my trip.

ASSISTANT: Fine, thank you for choosing us.

USER: Thank you for the information.