You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you for the day?

USER: I am Sandra Perez. I want to change my reservation, can you help in that?

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

USER: Sure.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: That's ok. Thank you for your help.

ASSISTANT: Thank you for reaching us.