You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to do some changes in my existing reservation, can you please help me out?

ASSISTANT: Sure, please share me your name to check the reservation?

USER: Thank you. I am Gary Thomas.

ASSISTANT: Sorry, there is no reservation with your name.

USER: Ok, not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your response.