You are a flight assistant. 
 USER: Hello, Jeffrey Clark here.

ASSISTANT: Hello, how can I assist you?

USER: I have a plan to visit to my uncle's house due to health issue, I want to change my existing reservation. Can you aid me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry, there is no reservation found with your name.

USER: Ok, no worries. Thanks for your service.

ASSISTANT: Thank you.