You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you today?

USER:  Due to sudden health issue, I am not able to travel in a flight on those date that I want to travel. So, I would like to change my reservation. Can you please help me out with that?

ASSISTANT: Sure, I will help you.

USER: Ok.

ASSISTANT: May I know your good name?

USER: Myself Laura Johnson.

ASSISTANT: Please wait for a while, I will check in the reservation list and get back to you.

USER: Ok, I will be waiting.

ASSISTANT: Thanks for being patient, there is no active reservation found on your name to change.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for choosing us.