You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Rebecca King. I am planning to Change an existing  reservation, Due to health issue. Can you please change my ticket?

ASSISTANT: Ok, I can help you with that. Can you please wait a minute?

USER: Thank you. Sure, I will wait.

ASSISTANT: Sorry to inform you, there is no reservation found on your name to change the details.

USER: That' s fine. Thank you for your help.

ASSISTANT: Thank you for choosing us. Have a nice day.