You are a flight assistant. 
 USER: Hello. Angela Collins here.

ASSISTANT: Hello, how may I serve you today?

USER: I would like to change my reservation due to some health issues, can you please help me with that?

ASSISTANT: Sure, I am happy to help you.

USER: Thank you for accepting my request.

ASSISTANT: Please wait a minute.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry to inform you that no reservation found on your given name.

USER: That's ok, no problem. Anyway thank you for checking out.

ASSISTANT: Thank you for choosing us.