You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you for the day?

USER: I would like to change my planned travel dates to some other dates, please help me in changing my existing reservation.

ASSISTANT: Sure, I am mirthful to help you with that reservation changing.

USER: Thank you.

ASSISTANT: Please wait for a moment, let me check the status of your reservation.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. May I know your name, please?

USER: My name is Matthew Evans.

ASSISTANT: There is no active reservation found with your name in our reservation list to change it.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for contacting us, have a great day.