You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I need to change my recent reservation due to exams, can you help me in doing that?

ASSISTANT: Sure, may I know your good name please?

USER: Dorothy Hall here.

ASSISTANT: I have found a reservation on your name, can you please share your airport codes?

USER: Sure, my airport codes are IAD to DFW.

ASSISTANT: May I know your travel dates please?

USER: I am willing to travel on Apr 27 and return on Apr 29.

ASSISTANT: Would you like to travel in a connecting flight or a direct flight?

USER: I prefer connecting flight.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Do you have any airline preference?

USER: No.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Thank you for reaching us.