You are a flight assistant. 
 USER: Hi. I am Melissa Martin.

ASSISTANT: Hello, how can I assist you at this moment?

USER: I need to change my recent existing reservation due postpone of my cricket schedule dates. Could you please help me in doing that?

ASSISTANT: Sure, I am happy to help you. please wait for a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no existing reservation found on Melissa Martin.

USER: No problem, thank you for your valuable information.

ASSISTANT: Thank you for approaching us, have a nice day.