You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Can you please let me know how may I help you?

USER: I want to change my existing reservation due to some health issue. Can you help me?

ASSISTANT: Sure, I am here to help you in changing the ticket details. Can you please let me know your name?

USER: Thank you, I am Patricia Harris.

ASSISTANT: Ok, please wait a minute.

USER: ok.

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

USER: Ok, no problem. Thank you for your information.

ASSISTANT: You are welcome. Thank you for choosing our travel agency.