Please note: Once an Admin is deleted, it cannot be restored.
To delete a Partner Center Admin:
Go to Partner Center > Administration > My Team
Click the icon next to the Admin you want to delete > Select Delete member.
Things to remember while deleting is if the member needs to be deleted or the Admin role needs to be deleted. If a member is not required to be an Admin anymore, then the Admin role can be denied but checking off the Admin role and NOT delete the member itself.
It's not possible to delete the user you are currently logged in as.