You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: On the name of Charles Hill, book a ticket on 05/27 as I want to reach my source point after completion of my seminar at SFO.

ASSISTANT: Sure, May I know the destination code?

USER: Thank you, my source point is at Detroit, DTW.

ASSISTANT: Please help me with your return date.

USER: I have to return on 05/29.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: Not a problem, I will check with another flights.

ASSISTANT: Thank you for opting us.

USER: Thank you for your support.