How to change a user’s role?
Just note that there is a simpler way to change the user role which is especially helpful when you do not know the current role of the user: ->set_role()
// NOTE: Of course change 3 to the appropriate user ID
$u = new WP_User( 3 );
// Remove role
$u->remove_role( 'subscriber' );
// Add role
$u->add_role( 'editor' );
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