# Special considerations for building master process flows - run process flow shape

## Introduction

The [run process flow](https://doc.wearepatchworks.com/product-documentation/process-flows/building-process-flows/process-flow-shapes/standard-shapes/run-process-flow-shape) shape is used to initialise another (sub) process flow from the current process flow. 

## Deploying parent & sub-process flows 

If a process flow is running in a [virtual environment](https://doc.wearepatchworks.com/product-documentation/virtual-environments/about-virtual-environments) and it includes a [run process flow](https://doc.wearepatchworks.com/product-documentation/process-flows/building-process-flows/process-flow-shapes/standard-shapes/run-process-flow-shape) shape, the process flow version being called (i.e. the sub-process flow) must exist in the same virtual environment. 

Make sure that you [deploy](https://doc.wearepatchworks.com/product-documentation/virtual-environments/implementing-virtual-environments/deploying-a-single-process-flow-to-a-virtual-environment) any required sub-process flows to the same environment as the 'parent' process flows. If a required sub-process flow version can't be found in a virtual environment, the flow run will fail with an error.