You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: As I have met with an emergency work, I want to change my existing reservation.

ASSISTANT: Sure, can I have your name please?

USER: My name is Gregory Harris.

ASSISTANT: Ok, please wait I will get back to you.

USER: Sure.

ASSISTANT: Thanks for waiting, we have not found any reservation with your given name.

USER: Ok, not a problem. Thank you for your service.

ASSISTANT: Thank you for contacting us.