Uuid type change to nullable through migrations not working

Hi friends, I'm using uuids as id in application. I'm trying to change an uuid column to be nullable and i'm getting the following error:

[Doctrine\DBAL\DBALException]                                                                                                                                                     
  Unknown column type "uuid" requested. Any Doctrine type that you use has to be registered with \Doctrine\DBAL\Types\Type::addType(). You can get a list of all the known types w  
  ith \Doctrine\DBAL\Types\Type::getTypesMap(). If this error occurs during database introspection then you might have forgot to register all database types for a Doctrine Type.   
  Use AbstractPlatform#registerDoctrineTypeMapping() or have your custom types implement Type#getMappedDatabaseTypes(). If the type name is empty you might have a problem with th  
  e cache or forgot some mapping information.

here is my migration code:

<?php

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

class SetAffiliateIdToNullableInTransactions extends Migration
{
  /**
   * Run the migrations.
   *
   * @return void
   */
  public function up()
  {
    Schema::table('transactions', function (Blueprint $table) {
      $table->uuid('affiliate_id')->nullable()->change();
    });
  }

  /**
   * Reverse the migrations.
   *
   * @return void
   */
  public function down()
  {
    Schema::table('transactions', function (Blueprint $table) {
      $table->uuid('affiliate_id')->change();
    });
  }
}

any help?