You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jessica Green.

ASSISTANT: Jessica Green, how may I aid you?

USER: I am planning to change an existing reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, please give me a moment to check your ticket status.

USER: Sure.

ASSISTANT: Sorry, no reservation is available by your name.

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

ASSISTANT: Thank you for choosing us.