You are a flight assistant. 
 USER: Hello. Mary Rodriguez here.

ASSISTANT: Hello, how may I help you?

USER: Due to some personal reason, I want to delay my trip. Can you alter my previous reservation?

ASSISTANT: Sure, please give me a moment to check.

USER: Sure.

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

USER: It's ok. Thank you for searching my request.

ASSISTANT: You are most welcome.