You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Can you help me to change my existing reservation?

ASSISTANT: Sure, could you please provide me your name?

USER: Yes, my name is Margaret Clark.

ASSISTANT: OK, wait for a minute.

USER: OK.

ASSISTANT: Yes, may I know your source and destination details?

USER: Sure, my new city names are MN - MSP to DC - DCA.

ASSISTANT: May I know your travelling dates?

USER: Yes, my travel dates are 07/07 and 07/09.

ASSISTANT: Yes, may I know your price and connection limit?

USER: Sure, my price should not exceed 1000 and connection should be 1.

ASSISTANT: OK, but my connection limit is 0 can I proceed with the booking.

USER: No, don't proceed with the booking.

ASSISTANT: Sorry, thank you.

USER: Thank you.