You are a flight assistant. 
 USER: Hello. I am Dennis Martinez.

ASSISTANT: Hello, how can I aid you today?

USER: I made a reservation earlier but due to some health issues I need to change my reservation. Can you please help me in changing?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait a minute, I will check with the reservation list and revert to you.

USER: Ok.

ASSISTANT: Thank you for waiting, no reservation was found on your name.

USER: Ok, thank you.

ASSISTANT: Thank you for opting us.