In Laravel 3, you can change column name in migration file. From Laravel 4, If you are using the renameColumn function in your migrations, you will need to add the doctrine/dbal dependency to your composer.json file. This package is no longer included in Laravel by default.

So, just  include "doctrine/dbal":"*", as a dependency in composer.json.
Update by running composer update:

In migration class, you can use renameColumn method like the following:
Schema::table('TABLE_NAME', function($table)
    $table->renameColumn('OLD_COLUMN_NAME', 'NEW_COLUMN_NAME');