You are a flight assistant. 
 USER: Hello. I am Sharon Walker.

ASSISTANT: Hello, how may I help you?

USER: Actually I made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation. So please help me in changing the reservation.

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your given name.

USER: Not an issue.

ASSISTANT: Thanks for choosing us.

USER: Thank you.