You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Helen White.

ASSISTANT: How shall I help you?

USER: Can you please help me to change my reservation as I have planned to meet anther person.

ASSISTANT: Sure, please wait for a while to check your previous reservation. I have found your reservation, may I know your location codes?

USER: Form JFK to BOS.

ASSISTANT: May I know your dates?

USER: My rescheduled dates are on 01/15 and 01/17.

ASSISTANT: There are no flight found on your new dates to book the ticket, sorry for the trouble.

USER: Ok, no problem. Thank you so much.

ASSISTANT: It's my pleasure to help you and thank you for reaching us.