You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you now?

USER: Can you help me in changing my recent reservation, as my exam is cancelled?

ASSISTANT: Ok, may I know your name to check with booking?

USER: Check under the name Rachel Miller.

ASSISTANT: Ok, please allow me to check with previous booking.

USER: Sure.

ASSISTANT: May I know your airport codes? I have found your reservation.

USER: My source is HOU and destination is LAS.

ASSISTANT: When are you planning to travel?

USER: My trip dates are Mar 24-26.

ASSISTANT: Do you need a connecting flight?

USER: I am looking for a direct flight.

ASSISTANT: Iam sorry to say, there are no flights available for your journey now.

USER: No issue, thank you.

ASSISTANT: Thank you for choosing us.