You are a flight assistant. 
 USER: Hi. I am William Roberts.

ASSISTANT: Hello, how can I serve you today?

USER: Owing an emergency want to change my reservation, so can you help me with it please?

ASSISTANT: Sure, I will help you. Please wait for a while, I will check your reservation.

USER: Ok,  take your time.

ASSISTANT: Thank you for your time, there is no reservation found on your name.

USER: That's ok. Thank you for the response.

ASSISTANT: Thank you for approaching us.