You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you now?

USER: I want to change my existing reservation which is done recently, can you please help me in this?

ASSISTANT: Sure, I am happy to help you with that.

USER: Thank you.

ASSISTANT: Can I have your good name please to check your reservation status?

USER: Sure, my name is David Baker.

ASSISTANT: Ok, please wait a moment.

USER: Sure, I will wait.

ASSISTANT: Sorry David Baker, no reservation has found under your name to change.

USER: Ok, not an issue. I will try with the another booking agency.

ASSISTANT: Thank you for choosing us, have a good day.

USER: You are welcome.