You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Betty Clark.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: Betty, there is no reservation found with your details.

USER: Ok, no problem.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your time.