You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Jonathan Nelson.

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

USER: I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, give me some time I will check and let you know.

USER: Ok.

ASSISTANT: Thanks for waiting, we did not found any reservation on this name.

USER: No issue.

ASSISTANT: Thanks for reaching us.

USER: Thank you for the information.