You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello.

USER: I am Elizabeth Lopez.

ASSISTANT: Lopez, how may I help you?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, I can do that for you. Please wait, let me check your reservation status in our database.

USER: Ok.

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

USER: Ok, thanks for sharing the information.

ASSISTANT: You are welcome and thank you for choosing us.