ModifyExistingEnum.php

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class ModifyExistingEnum extends Migration
{
    public function up()
    {
        $values = implode(', ', array_map(function ($type) {
            return "'" . $type . "'";
        }, ['your', 'new', 'types', 'here']));

        DB::statement('ALTER TABLE my_table DROP CONSTRAINT my_table_my_column_check,
                ADD CONSTRAINT my_table_my_column_check CHECK (my_column::text = ANY (ARRAY['. $values . ']::text[]))');
    }
}