You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Betty Jackson here.

ASSISTANT: Betty, how can I assist you today?

USER: I want to change my reservation, due to some health issue. Can you please help me?

ASSISTANT: Sure, I can help you. Let me check your reservation status in our database.

USER: Ok.

ASSISTANT: Happy to inform you, I found a reservation by your name. Please tell us your travel dates.

USER: My new travelling dates are from 09/23 till 09/25.

ASSISTANT: Ok, let me know your airport codes.

USER: My new airport codes are from DCA to SFO.

ASSISTANT: Ok, please wait for a while.

USER: Ok, take your time.

ASSISTANT: Happy to inform you, there is a flight-1021 available with UA airlines and the ticket fare is 100 only. Shall I book the ticket?

USER: Please proceed.

ASSISTANT: Your ticket is booked successfully.

USER: Thank you for booking.