You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I would like to change my father's reservation because he want to spend some more time with his friend in Los Angeles, can you please help me?

ASSISTANT: Sure, may I know your father's name to change his reservation?

USER: Yes, his name is Thomas Lopez.

ASSISTANT: Please give me a moment to check the database.

USER: Sure.

ASSISTANT: Sorry, we could not find a reservation on your father's name.

USER: That's fine, not an issue. Thank you for checking.

ASSISTANT: Thank you for reaching us.