You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I would like to change my existing flight reservation that has been booked earlier this week.Could you please help me in re-modifying my dates in the reservation?

ASSISTANT: Sure, I am happy to help you in modifying the  ticket details. Can you please let me know your good name to check the ticket status?

USER: Myself Jack Gonzalez.

ASSISTANT: Ok, please give me a moment.

USER: Ok.

ASSISTANT: I am sorry to inform you that, I have not found any active reservation on your name to modify.

USER: It's ok. Thank you.

ASSISTANT: Most welcome. Thank you for reaching us. Have a nice day.