Example how to make transition of workflow using processes in Oro

process.yml

definitions:
    order_create:
        label: 'Trigger "final_step_transition" transition for new FooBar entity if FooBar->isSubscribed() === true'
        entity:  ACME\Bundle\DemoBundle\Entity\FooBar
        actions_configuration:
            - @transit_workflow:
                conditions:
                    @true: $subscribed
                parameters: [$.data, 'final_step_transition']
triggers:
    order_create:
        -
            event:    create
            priority: 5
            queued:   false

services.yml

services:
    acme_demo.action.transit_workflow:
        class: ACME\Bundle\DemoBundle\Model\Action\TransitWorkflow
        arguments:
            - @oro_workflow.context_accessor
            - @oro_workflow.manager
        tags:
            - { name: oro_workflow.action, alias: transit_workflow }

TransitWorkflow.php

<?php

namespace ACME\Bundle\DemoBundle\Model\Action;

use Oro\Bundle\WorkflowBundle\Exception\ActionException;
use Oro\Bundle\WorkflowBundle\Exception\InvalidParameterException;
use Oro\Bundle\WorkflowBundle\Model\Action\AbstractAction;
use Oro\Bundle\WorkflowBundle\Model\ContextAccessor;
use Oro\Bundle\WorkflowBundle\Model\WorkflowManager;

/**
 * Performs workflow transition
 */
class TransitWorkflow extends AbstractAction
{
    /**
     * @var WorkflowManager
     */
    protected $workflowManager;
    
    /**
     * @var string
     */
    protected $entity;
    
    /**
     * @var string
     */
    protected $transition;
    
    /**
     * @param ContextAccessor $contextAccessor
     * @param WorkflowManager $workflowManager
     */
    public function __construct(ContextAccessor $contextAccessor, WorkflowManager $workflowManager)
    {
        parent::__construct($contextAccessor);
        $this->workflowManager = $workflowManager;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function executeAction($context)
    {
        $entity = $this->contextAccessor->getValue($context, $this->entity);
        $transition = $this->contextAccessor->getValue($context, $this->transition);
        $workflowItem = $this->workflowManager->getWorkflowItemByEntity($entity);
        if (!$workflowItem) {
            throw new ActionException('Cannot transit workflow, entity doesn\'t have workflow.');
        }
        $this->workflowManager->transit($workflowItem, $transition);
    }
    /**
     * {@inheritdoc}
     */
    public function initialize(array $options)
    {
        if (isset($options['entity'])) {
            $this->entity = $options['entity'];
        } elseif (isset($options[0])) {
            $this->entity = $options[0];
        } else {
            throw new InvalidParameterException('Option "entity" is required.');
        }
        if (isset($options['transition'])) {
            $this->transition = $options['transition'];
        } elseif (isset($options[1])) {
            $this->transition = $options[1];
        } else {
            throw new InvalidParameterException('Option "transition" is required.');
        }
    }
}