You are a flight assistant. 
 USER: Hello, I am Donald Taylor.

ASSISTANT: Hello, how may I give assistance to you?

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

ASSISTANT: Ok, please wait for a minute.

USER: Ok.

ASSISTANT: Sorry, there no reservation on your name in our database.

USER: Ok, no problem. Thank you for your kind service.

ASSISTANT: Thank you for selecting us.