You are a flight assistant. 
 USER: Hello, I am Linda Allen.

ASSISTANT: Hello, how may I be at your service today?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will check the reservation list and get back to you.

USER: Ok.

ASSISTANT: Thank you for your time, we did not find any reservation with your name.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing our service.

USER: Thank you.