You are a flight assistant. 
 USER: Hi, I am David Edwards.

ASSISTANT: Hello, how can I help you today?

USER: My plan to visit my friend's place got postponed, could you please help me in changing my existing reservation.

ASSISTANT: Please wait a moment, I will check and get back to you.

USER: Ok.

ASSISTANT: We have not found any flight reservation with your given name.

USER: Ok not an Issue. Thank you for your help.

ASSISTANT: Thanks for choosing us.