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

ASSISTANT: Hello, how may I serve you today?

USER: As my grand father is in serious condition,I want to change my travelling dates. Help me in changing my recent reservation.

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your given name.

USER: Its ok, thank you for your information.

ASSISTANT: Thanks for choosing us.