You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, may I know your name to check with the status?

USER: Jack Moore.

ASSISTANT: Please wait a moment while I check with the status.

USER: Ok.

ASSISTANT: Thank you for waiting, regret to inform that there is no active reservation found under your name to change.

USER: No issue. Thank you.

ASSISTANT: Thank you for reaching us.