You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Due to my health conditions, I want to change my recent reservation.Can you help me with that?

ASSISTANT: Ok, please can I know your name to check?

USER: Sandra Robinson here.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Ok, thank you for waiting. Sorry as per our records of reservation no ticket is booked on your name. Thank you choosing our agency.

USER: No issue, Thanks for the information.