You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Frank Williams.

ASSISTANT: Please let me know how may I help you?

USER: I would like to change my reservation as my niece is getting married, can you please help me out?

ASSISTANT: Sure, I will help you in changing your ticket.

USER: Thank you.

ASSISTANT: Ok, please wait a minute.

USER: Sure, take your time.

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

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

ASSISTANT: You are welcome. Thank you for reaching us.