You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is William Martinez.

ASSISTANT: How may I help you?

USER: I want to change my existing reservation because I want to stay few more days here, can you please hep me for that?

ASSISTANT: Sure, I will help you.

USER: Ok.

ASSISTANT: I found your reservation, may I know your new airport codes?

USER: My airport codes are EWR and BOS.

ASSISTANT: Can you please tell me your planning dates?

USER: My travelling dates are 10/10 and 10/12.

ASSISTANT: Please wait a moment.

USER: My price should not exceed 200.

ASSISTANT: I found a flight-1002 with single connection and the airline is Southwest. It costs you 100.

USER: That's fine, please proceed for booking.

ASSISTANT: Your ticket is booked.

USER: Thank you for booking.

ASSISTANT: Thank you for reaching us.

USER: Welcome.