You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you?

USER: Myself David Baker. I want to change my flight reservation as my project got postponed, can you please help me?

ASSISTANT: Sure, Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Sad to hear that. Anyway, thank you for checking.

ASSISTANT: Thank you for opting us.

USER: You are welcome and thank you for checking.