You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am John Garcia.

ASSISTANT: How may I help you?

USER: I would like to modify my previous flight ticket booking, can you please help me?

ASSISTANT: Sure, I am gleeful to help you. Can you please hold on for a moment?

USER: Sure, I will wait for your response.

ASSISTANT: Sorry to inform you, there is no reservation under your name to modify.

USER: Ok, that's fine. Thank you for your valuable information.

ASSISTANT: Thanks a lot for choosing our travel agency.

USER: You are welcome.