You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,. May I know your name?

USER: I am Matthew Smith.

ASSISTANT: How can I aid you?

USER: I want to change my existing reservation due to my friend's birthday party place has been changed. Can you help me in doing this?

ASSISTANT: Sure, I will assist you.

USER: Thank you.

ASSISTANT: Please wait a while let me check and let you know you the status.

USER: Sure.

ASSISTANT: Thank you for your time,  I have checked in reservation list to change your existing reservation details, but could not find any reservation with your name.

USER: Ok, no issues. Thanks for your kind response.

ASSISTANT: Thank you for availing us. Have a nice day.