CommandCost ret = CheckOwnership(v->owner);

	if (ret.Failed()) return ret;

	VehicleOrderID order_number = GB(p1, 20, 8);

	Order *order = v->GetOrder(order_number);

	if (order == NULL || order->IsType(OT_IMPLICIT)) return CMD_ERROR;

	ModifyTimetableFlags mtf = Extract<ModifyTimetableFlags, 28, 2>(p1);

	if (mtf >= MTF_END) return CMD_ERROR;

	int wait_time   = order->wait_time;

	int travel_time = order->travel_time;

	int max_speed   = order->max_speed;

	switch (mtf) {

		case MTF_WAIT_TIME:

			wait_time = GB(p2, 0, 16);

			break;

		case MTF_TRAVEL_TIME:

			travel_time = GB(p2, 0, 16);

			break;

		case MTF_TRAVEL_SPEED:

			max_speed = GB(p2, 0, 16);

			break;

		default:

			NOT_REACHED();

	}

	if (wait_time != order->wait_time) {

		switch (order->GetType()) {

			case OT_GOTO_STATION:

				if (order->GetNonStopType() & ONSF_NO_STOP_AT_DESTINATION_STATION) return_cmd_error(STR_ERROR_TIMETABLE_NOT_STOPPING_HERE);

				break;

			case OT_CONDITIONAL:

				break;

			default: return_cmd_error(STR_ERROR_TIMETABLE_ONLY_WAIT_AT_STATIONS);

		}

	}

	if (travel_time != order->travel_time && order->IsType(OT_CONDITIONAL)) return CMD_ERROR;

	if (max_speed != order->max_speed && (order->IsType(OT_CONDITIONAL) || v->type == VEH_AIRCRAFT)) return CMD_ERROR;

	if (flags & DC_EXEC) {

		if (wait_time   != order->wait_time)   ChangeTimetable(v, order_number, wait_time,   MTF_WAIT_TIME);