You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how could I help you today?

USER: I am Gregory King. I want to change my existing reservation due to postpone of my client meeting.

ASSISTANT: Sure, please wait for a while I will check and get back to you.

USER: Ok.

ASSISTANT: We found a reservation with your provided name. Can you please share me your new reservation details?

USER: My departure day is 01/27, return day is 01/29. My source and destination airport codes are IL - ORD, CA - OAK.

ASSISTANT: Just hold on a minute.

USER: Ok.

ASSISTANT: We found a flight with an airline Spirit and flight number is 1004 with price 100.

USER: You can proceed to booking.

ASSISTANT: Your ticket has been booked on name of Gregory King.

USER: Thank you.

ASSISTANT: Thank you for reaching us help.