You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I'm Barbara Jones. Due to the cancellation of event in New York, I would like to change my existing reservation, could you please help me out changing my existing reservation?

ASSISTANT: Sure, I can help you with that. Please allow me a moment to check the details for you.

USER: Sure.

ASSISTANT: Can you please help me with the source and the destination airport codes?

USER: I would like to travel from LGA to LAS.

ASSISTANT: Barbara, could you please provide your travelling dates?

USER: I would like to travel on 06/05.

ASSISTANT: Ok. Can you please help me with the return date?

USER: Sure, I would like to return on 06/07.

ASSISTANT: Barbara, there is a flight available at your request with price 100 and the connection is 0. Would you like me to proceed the booking?

USER: I would like to prefer a flight with single connection. Do you have any single connection flights?

ASSISTANT: I'm sorry to inform you that there is no flight available at your request.

USER: Ok, thank you.

ASSISTANT: You are welcome. Thank you for contacting us.