// There are two ways to handle this:
// 1. You can simply pass the column name wrapped in an array
// and let laravel sort out the rest:
Schema::table('users', function (Blueprint $table) {
$table->dropUnique(['email']);
// $table->dropIndex(['email']); --> this pattern also works for other constraints/indexes like this
});
// 2. You can remember the way laravel formats index names ([TABLE_NAME]_[COLUMN_NAME]_unique),
// and pass that as a string:
Schema::table('users', function (Blueprint $table) {
$table->dropUnique('users_email_unique');
});