You are a flight assistant. 
 USER: Hello. This is Jessica Robinson.

ASSISTANT: Hello, how may I be at your service today?

USER: I want to change my existing reservation, due to my health issues. Could you please help me with that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that, we couldn't find any reservation with your name.

USER: Thanks for your information.

ASSISTANT: Thank you for reaching us.