You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Jack Thompson here.

ASSISTANT: How may I assist you now?

USER: I would like to change my recent reservation because of some personal work, can you help me with this?

ASSISTANT: Jack Thompson, please allow me to check with your previous booking.

USER: Sure, take your own time.

ASSISTANT: Sorry to say, there are no flights available for your journey. No reservation was found by your name.

USER: That's fine, thanks for your information and help.

ASSISTANT: Thank you for choosing our services.