You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I render you at this moment?

USER: I am David Davis. Could you please help me with booking a flight ticket from SFO to PHL.

ASSISTANT: Sure, I will help you. Please send your preferable date of journey.

USER: My preferable dates are Feb 19 and Feb 21.

ASSISTANT: Do you have any class or time limitations?

USER: I want economy class.

ASSISTANT: There is a connecting flight available with Delta airline in economy class, shall I book it?

USER: Yes, please proceed.

ASSISTANT: Your booking is done with flight number 1013. Happy journey.

USER: Thank you for your help.

ASSISTANT: You are welcome, have a nice day.