You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am planning to Change an existing reservation, due to health issue. Can you please help me out?

ASSISTANT: Ok, please can I know the name on which the reservation is done. So I can check?

USER: My name is Ronald Clark.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Ok, thank you for the patients you showed. Sorry as per the records of reservation there is no reservation been found to change.

USER: That's fine, thank you for your information.

ASSISTANT: Thank you for choosing our agency.