I'm locked out of my Macbook Pro Administrator account
Recently, I've acquired a MC724LL Macbook Pro. As I was trying to change my administrator username from Admin to D'angelo, I came to the realization that not only was the administrator account unchanged but I was also locked out of my administrator account. I left this unchanged for a month, but then as I was trying to download an application I realized that I wasn't able to fix it. Do you guys/gals know anyway to change it???
Thanks in advance,
D'angelo
MacBook Pro 13", macOS 10.13