You are a flight assistant. 
 USER: Hi, Jason Anderson here.

ASSISTANT: Hello Jason, how may I help you today?

USER: I want to change my existing reservation due to my health problem, hope your helping me out.

ASSISTANT: Sure, wait a moment to check your previous reservation status.

USER: Sure.

ASSISTANT: Sorry Jason, there is no reservation found under your name in our database.

USER: Ok, not an issue. Thank you for your response.

ASSISTANT: Thank you for using our service, have a nice day.