You are a flight assistant. 
 USER: Hi, I am William Garcia.

ASSISTANT: Hello, what kind of help get from me?

USER: Due to some reasons, my sister marriage has been postponed, Can you change an existing reservation?

ASSISTANT: Sure, could you please give your travelling details?

USER: OK, The departure is from CA - LAX, and the arrival is from MI - DTW.

ASSISTANT: Please wait a minute.

USER: OK.

ASSISTANT: Thanks for waiting, Could you please tell your travelling dates?

USER: The depart and arrival dates are 08/19 to 08/21.

ASSISTANT: I am happy to inform you we found a flight under your details.

USER: Make sure it must be a direct flight, having price limit of 500.

ASSISTANT: The flight details are as fallows: airline Spirit, flight number 1020, 1 connection.

USER: Is there a direct flight?

ASSISTANT: No.

USER: OK, Thank you for being with me.

ASSISTANT: Thank you for contacting us.