the home user admin passed away. How do i unlink my account and become admin? Ijust purchased a lifetime account 
I believe you will need to delete that account or I would first try just sign out, then login with your shinny new Plex Lifetime account credentials. That would be on the same Plex Media Server with that computer and have admin access.
Example:
Then proceed to Authorised devices in settings and delete the old server’s Tile if it is present.
Then in General Settings give yourself a New friendly name for the Plex Media Server.
You will need to set a new Plex Home with managed accounts if still required.
If you are talking about the actual server machine, depending on the type of device and operating system, it’s something like this procedure: https://support.plex.tv/articles/204281528-why-am-i-locked-out-of-server-settings-and-how-do-i-get-in/
If it’s Windows, you can also use this procedure: You need to reclaim your server, but don't dare to touch the Windows Registry
It is a different machine. I logged into my account with anew computer and it shows me as a managed account. I can’t delete old friends etc from my account. When I do it say only home admin can
This can only mean that you used a different account than what you are using now to post in this here forum.
Because this account here is not in any Plex Home and is not a managed account. And it has a fresh Plex Pass.
Make sure that you are NOT picking “Login with Google”. Use “Login with Email/Username”
Do you have access to the server / account of the prior admin?
If not, then your only choice may be to leave the home. I do not recall right now how to do so, but if this is what you need to do, someone else will surely say how.
I do. It have access. If anyone knows how to leave home please let me know. And thank you for the help
Ok, I tested it out. Click the wrench icon to go to settings. On the left-hand side, click on Plex Home. This will list all Home users, Including yourself.
Point at your name on the list, and on the right you should see the text Set PIN appear. To the right of that is an X button. That ought to let you choose to leave home.
