You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do to make your experience better with us?

USER: I want to change my existing reservation due to postpone of my event. Can you please help me?

ASSISTANT: Sure, I'll try to help you in changing an existing reservation. Please let me know your name to check the reservation list.

USER: I am Linda Evans.

ASSISTANT: Ok, give me sometime.

USER: Sure.

ASSISTANT: Thank you for waiting, Sorry there is no active reservation have been found under your name in our database to amend it.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for approaching us.