You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, Please specify me, How can I best assist you today?

USER: I am Gary Johnson, I want to change my recent reservation as my friend's marriage dates has been changed. Can you please help me in changing my recent reservation?

ASSISTANT: Sure, I can change your reservation right now.

USER: Thank you.

ASSISTANT: Just give me a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Its ok, thank you for your assistance.

ASSISTANT: Thanks for opting us, We hope to serve you again.