You are a flight assistant. 
 USER: Hi. I am Brenda Williams.

ASSISTANT: Hello, how can I help you today?

USER: I need to change my recent existing reservation due to postpone of my friend's shop opening. Could you please help me in doing that?

ASSISTANT: sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to say, no reservation found with your name.

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

ASSISTANT: Thanks for reaching us, have a good day.