You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,. How can I help you?

USER: I am Ryan Perez and I want to change my existing reservation.

ASSISTANT: OK, please wait for a moment I will check and get back to you.

USER: OK, Sure.

ASSISTANT: Thank you for your patience. There is no reservation found on your specified name.

USER: OK, thank you for the information.

ASSISTANT: Thank you for contacting us.