Creating a new administrator user account on High Sierra

[Monzo97]

I recently tried to change the name of my administrator user account but this made the account turn into a standard one. Now I can't put in the administrator username and password when requested, which is a big problem when it comes to installing things. I have High Sierra (not sure if there is any other info I should include?). Does anyone know of any safe ways to make a new administrator account? Anything would be much appreciated. Thanks!

 

[BobanVelickovic]

I have the same problem. Have you found a solution??