You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I render you today?

USER: I am Jeffrey Jones.

ASSISTANT: Ok.

USER: Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, please standby.

USER: Ok.

ASSISTANT: Thanks for waiting, your name is not there in the reservation list to proceed further.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us, Have a great day.