You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I amend you?

USER: I am Margaret Green. Due to my health problem I want to change my reservation, can you please help me that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: We are glad to inform you that, reservation was found on your name. Please share the details to proceed further.

USER: Ok, My airport codes are from DFW to EWR. I would like to leave between 12/17 and 12/19.

ASSISTANT: Ok. We found a Delta airline with a connecting flight. 1009 is the flight number. Shall I continue to book?

USER: Ok, please book this ticket.

ASSISTANT: Your reservation is done successfully.

USER: Thank you so much.

ASSISTANT: Thank you.