Laravel migrate - multiple migrations (files) in one go

Say, I have multiple migration files updating single table.

e.g.

2016_03_20_072730_create_tasks_table.php
2016_03_20_075467_create_tasks_table.php

... which came from repo by different team members. Each is adjusting something in table, e.g. adding a column.

When I try to:

php artisan migrate

I get error:

PHP Fatal error:  Cannot declare class CreateTasksTable, because the name is
eady in use in U:\www\b10\database\migrations\2016_03_20_072737_create_tasks_
le.php on line 30


  [Symfony\Component\Debug\Exception\FatalErrorException]
  Cannot declare class CreateTasksTable, because the name is already in use

How should one deal with situation as described above?

EDIT

Here is the code:

2016_03_20_072730_create_tasks_table.php:

class CreateTasksTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
       Schema::table('tasks', function ($table)
       {
           $table->string('task1');
       });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('tasks');
    }
}

2016_03_20_075467_create_tasks_table.php:

class CreateTasksTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
    Schema::table('tasks', function ($table)
        {
            $table->string('task2');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('tasks');
    }
}