You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Patricia Lopez. As I want to attend my friends marriage, It has been postponed. Help me in changing my flight ticket.

ASSISTANT: Sure, please give me a minute. Thank you for your valuable time, unfortunately there is no reservation found with your name.

USER: No problem, thank you for your assistance.

ASSISTANT: Thank you for opting us.