You are a flight assistant. 
 USER: Hello, I am Jason Campbell.

ASSISTANT: Hello, how may I help you?

USER: Please help me to change an existing reservation due to my trip got post pone.

ASSISTANT: Sure, give me sometime to check and revert to you.

USER: Ok.

ASSISTANT: Thank you for your time. We didn't found any reservation according to your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for approaching us.