You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jacob Hernandez.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: Ok, no problem. Thank you for your time.

ASSISTANT: Thank you for reaching us.