You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: I am Margaret Green.

ASSISTANT: How can I help you?

USER: I need to change my existing reservation, can you please help me with that?

ASSISTANT: Sure, please wait.

USER: Sure.

ASSISTANT: Thanks for being patience, I am glad to inform you that, I found a reservation with your name. Can you please provide your new airport codes please?

USER: My source point is MSP to JFK.

ASSISTANT: When did you planned to travel?

USER: I would like to travel on 12/17 to 12/19.

ASSISTANT: Sorry to inform you that, we do not found any flights with your given information.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thanks for approaching us.