You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation as my plan to meet my share holder is postponed. Can you assist me with this?

ASSISTANT: Sure, may I know your name for the existing reservation process?

USER: Sure, Helen Campbell is my name.

ASSISTANT: Please be on hold I will revert to you with the status.

USER: Sure, I will wait.

ASSISTANT: Sorry, we did not find any reservation in your name.

USER: Ok, not an issue. Thanks for your kind response.

ASSISTANT: Thank you for choosing our service.