You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER:  I want to do some modifications in my previous reservation, can you please help me?

ASSISTANT: Sure. Please provide your name.

USER: My name is Gary Lewis.

ASSISTANT: Sorry, no reservation is found.

USER: No issues, thank you for information.

ASSISTANT: Thank you for choosing us.

USER: You are welcome.