<?php

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

class ConstrainComments extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        //
        //
        Schema::table('comments',function($table)
        {

            $table->foreign('userID')->references('userID')->on('users');
            $table->foreign('workID')->references('workID')->on('works');


        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        //
        Schema::table('comments', function ($table) {

        $table->dropForeign('comments_userID_foreign');
        $table->dropForeign('comments_workID_foreign');
      });
    }
}

<?php

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

class ConstrainComments extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        //
        //
        Schema::table('comments',function($table)
        {

            $table->foreign('userID')->references('userID')->on('users');
            $table->foreign('workID')->references('workID')->on('works');


        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        //
        Schema::table('users', function ($table) {

        $table->dropForeign('comments_userID_foreign');
        $table->dropForeign('comments_workID_foreign');
      });
    }
}

--- 
+++ 
@@ -32,7 +32,7 @@
     public function down()
     {
         //
-        Schema::table('users', function ($table) {
+        Schema::table('comments', function ($table) {
 
         $table->dropForeign('comments_userID_foreign');
         $table->dropForeign('comments_workID_foreign');
Correct drop table referencing wrong table
