Ps4 name change under 18 years?

Tachöön, I have on my Ps4 two accounts, main account and a sub-account.
I would like to change my main account the name of what I use in the sub-account, because the sub-account is a stupid parental control inside, this is unfortunately not possible because… How can I change that?

So you can't change your PSN name, but you can change your normal name, which you can do through your main account.