You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am David Green.

ASSISTANT: How can I serve you?

USER: Owing to an emergency, I want to change an existing reservation.

ASSISTANT: Sure, I can help you out. Give me a minute.

USER: Sure.

ASSISTANT: Thanks for your time. We found a reservation by this name. Can I  know your updates journey dates?

USER: I would like to fly on 06/24 and return on 06/26.

ASSISTANT: Please share me your airport codes.

USER: My airport codes are TX - IAH, NV - LAS.

ASSISTANT: Do you need any break?

USER: Yes, I need a halt.

ASSISTANT: We found a Hawaiian airline, flight number:1022 and the price is 200.

USER: You can proceed to booking.

ASSISTANT: Your flight ticket has been reserved.

USER: Thank you.

ASSISTANT: Thank you.