You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I had planned a trip but due to my mother's health problem I need to postpone it, so can you please help me to change my reservation?

ASSISTANT: Sure, I am here to assist you. May I know your name?

USER: My name is Frank Martinez.

ASSISTANT: Thank you. Please wait for a while, let me check your reservation status in our database.

USER: Sure, I am right here.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: No problem, thank you anyway.

ASSISTANT: You are welcome and thank you for choosing us.