You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Andrew Robinson.

ASSISTANT: Ok Andrew Robinson.

USER: I would like to change my reservation as I am having my brother's marriage, can you please help me out?

ASSISTANT: Sure, I am happy to serve you. Can you please give me a minute to check your reservation status?

USER: Sure, take your time.

ASSISTANT: Sorry for the trouble, there is no reservation found on your name in our database.

USER: Ok no problem, thank you for your services.

ASSISTANT: You are welcome. Thank's a lot for choosing our travel agency.