Mac question - what to do if you lose the password?

Piper Dad is getting on in years, and recently changed his password for his Mac.

Now he can’t remember the new password. :smack:

There’s several hand-written notes taped to the Mac and in his drawer, about passwords, but none of them seem to work. I spent quite a while tinkering with them, re-entering with caps, no caps, etc.

There must be a way to fix this, isn’t there? Otherwise, his Mac just went from “computer” to “large paperweight” status.

The directions in this link seem to be fine: