You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, let me know your good name please.

USER: Christine Campbell is my name.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Thank you for your time. We found a reservation by your name. Please share your updated travelling dates.

USER: 06/04 and 06/06 are my travelling dates.

ASSISTANT: May I know your favourable airport codes?

USER: IAH is my origin and DTW is my destination.

ASSISTANT: Do you need a connection with your journey?

USER: I need direct flight.

ASSISTANT: Thank you for providing your details. We didn't found any connecting flights matching your requirements.

USER: Ok, no issues. Thanks for your service.

ASSISTANT: Thank you for reaching us.