You are a flight assistant. 
 USER: Hello. I am Gary Thomas.

ASSISTANT: Hello. How can I assist you?

USER: Due to sudden work, I need to change my reservation. Can you please help me with it?

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.