You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: Margaret Miller here, I need to change my reservation as my plan to go for trekking got postponed. Can you help me?

ASSISTANT: Sure, I will aid you with that. Please wait a moment.

USER: Sure.

ASSISTANT: I have found your reservation. Can you please mention your preferable travel dates?

USER: I will start on June 19th and return on June 21st.

ASSISTANT: May I know your preferable airport code names for further process?

USER: My origin is DEN and destination is SFO.

ASSISTANT: Do you have any limits on number of connections?

USER: Yes, I need 1 connection only.

ASSISTANT: Do you have any another specifications?

USER: No.

ASSISTANT: Ok, please hold on a moment.

USER: Sure.

ASSISTANT: Frontier airline flight available with connection limit 1 and fare is 100, shall I confirm this economy class flight?

USER: Fine, please proceed.

ASSISTANT: Your flight ticket is booked successfully, flight number is 1001.

USER: Thanks for your support.

ASSISTANT: You are welcome Margaret Miller.