You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation which was made on the name of Lisa Hernandez. Can you help me with it?

ASSISTANT: Sure, I am here to help you. Please wait for a moment, I will check your reservation.

USER: Ok.

ASSISTANT: Thank you for your time. There is no reservation found on your name.

USER: Ok, thank you for the response.

ASSISTANT: Thank you for reaching us.