Update status with Gravity Forms

    /**
     * When processing Gravity Form #7 update Offer (which is a custom post type) post status to accepted (which is a custom post status)
     *
     * @since    1.0.0
     */
    function oxygen_child_accept_offer ( $entry, $form ) {

        $gf_offer_id = $entry[4];       // Offer ID (hidden field), must be dynamically populated with the post ID for this to work
        global $wp_query, $post;

        if ( $gf_offer_id ) {
            // Update the Offer with the status accepted ****************************
            $offer_post = array(
                'ID' => $gf_offer_id,
                'post_status'   => 'accepted',
                // this is a custom status, it could have been 'publish','draft', etc.
            );

            wp_update_post( $offer_post );
                    // ****************************************************************************************************
        }
    }
    // Gravity Form #7, change the ID to your form's ID
    add_action( 'gform_after_submission_7', 'oxygen_child_accept_offer', 10, 2 );