You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, can you please mention your name to check your reservation details in our database?

USER: Jennifer Robinson here.

ASSISTANT: Please wait for a while, let me check your reservation status.

USER: Ok.

ASSISTANT: Sorry, I did not find any reservation by your name in our database.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thanks for reaching us.