SparkServiceProvider.php

<?php

class SparkServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        $this->app->singleton(
            \Laravel\Spark\Contracts\Interactions\Settings\Profile\UpdateContactInformation::class,
            \App\SparkExtensions\UpdateContactInformation::class
        );
    }
}