You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Joshua Harris here.

ASSISTANT: Harris, how can I help you today?

USER: I need to change my existing reservation, can you please help me in this?

ASSISTANT: Sure, I am happy to help you. Please wait for a moment.

USER: Please take your time.

ASSISTANT: Sorry Harris, no reservation found under your name in our database.

USER: Thank you for searching the details.

ASSISTANT: Thank you for choosing us.