> For the complete documentation index, see [llms.txt](https://doc.wearepatchworks.com/product-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.wearepatchworks.com/product-documentation/virtual-environments/implementing-virtual-environments/configuring-a-virtual-environment-version/configuring-virtual-environment-replacements/replacement-instances.md).

# Replacement instances

## Introduction

Having [chosen to configure instance replacements for a virtual environment](/product-documentation/virtual-environments/implementing-virtual-environments/configuring-a-virtual-environment-version/configuring-virtual-environment-replacements.md#configuring-replacements-for-a-virtual-environment-version), a new replacement rule is displayed, ready for you to configure:

<figure><img src="/files/liynkMtSM5uOnCkXelPh" alt=""><figcaption></figcaption></figure>

Having defined the first rule, you can add more - you must create one replacement rule for every instance that you need to replace in every process flow that will run in this environment.

## Defining replacement rules for an instance

{% stepper %}
{% step %}
**Select the required connector**

Use the `connector` dropdown list and choose a connector that's included in any process flows that you'll be running in this virtual environment:

<figure><img src="/files/ORI5EvaRDrx8ChSTSs9D" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
As you work through your replacement configuration, it's helpful to view related ['master' process flows](/product-documentation/virtual-environments/implementing-virtual-environments/creating-a-master-process-flow.md) in another browser tab. You can duplicate a Patchworks browser tab and navigate to a different page whenever needed.
{% endhint %}
{% endstep %}

{% step %}
**Select the required ORIGINAL connector instance**

Use the `original` dropdown list to select an instance in a 'master' process flow that must be replaced when this process flow runs in the given virtual environment - for example:

<figure><img src="/files/hT8Vz4ziDk7KuCAtI82z" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}
**Select the required REPLACEMENT connector instance**

Use the `replacement` dropdown list to select the replacement instance that must be used when this process flow runs in the given virtual environment - for example:

<figure><img src="/files/PwIFX421jSDmW27JpXD7" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}
**Confirm your selections**

Click the `create` button (associated with this replacement rule) to confirm your selections:

<figure><img src="/files/rrMgKwV8AlDejbtPqzYL" alt=""><figcaption></figcaption></figure>

The rule is added:

<figure><img src="/files/E8AJxCTMsQav7mQiw1BW" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
Once a rule is confirmed, it can't be edited. If you need to change a replacement rule, use the 'trash' icon to remove it and add a new one.
{% endhint %}
{% endstep %}

{% step %}
**Add more replacement rules for connector instances**

To add another replacement rule for a connector instance, click the top-right `create` button:

<figure><img src="/files/YJwtR5VRb1DgDI6G8YB9" alt=""><figcaption></figcaption></figure>

Update the new rule as required, then click the associated `create` button to confirm your selections:

<figure><img src="/files/P8kcv8FlVTCbbtrKI8WV" alt=""><figcaption></figcaption></figure>

Repeat as many times as needed to define all required instance replacements for all process flows that will be running in this virtual environment.

{% hint style="info" %}
If you don't want to define ALL instance replacements now, that's OK. For example, you might choose to add the minimum number of replacements needed for [testing](/product-documentation/virtual-environments/implementing-virtual-environments/testing-a-process-flow-against-a-virtual-environment.md), then define remaining rules (in a [new draft](/product-documentation/virtual-environments/implementing-virtual-environments/configuring-a-virtual-environment-version/understanding-virtual-environment-versions.md)) later, after initial testing is complete.
{% endhint %}
{% endstep %}
{% endstepper %}