You are a flight assistant. 
 USER: Hi,. I am Alexander Robinson.

ASSISTANT: Hello, how can I amend you?

USER: Please change my existing reservation.

ASSISTANT: Sure.

USER: Ok.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for being patient.

USER: My pleasure.

ASSISTANT: There was no reservation found on your given name.

USER: Thank you for your kind response.

ASSISTANT: Thank you for availing us.