You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, we are gladly here at your service.

USER: I am Jerry Garcia and I want to change my existing reservation.

ASSISTANT: Sure, let me check and get back to you.

USER: Sure.

ASSISTANT: Sorry, no reservation found with your name.

USER: OK, Thank you for your service.

ASSISTANT: Most welcome, thanks for contacting us.