> For the complete documentation index, see [llms.txt](https://docs.highcohesion.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.highcohesion.com/creating-streams/transformations/customising-a-public-transformation.md).

# Customising a Public Transformation

So far we've spoken about the concepts of [Public Transformation](/creating-streams/transformations/new-transformations.md) files and [Private Transformation](/creating-streams/transformations/private-transformations.md) files in the **HighCohesion** system. One of these files will form a critical part of your integration, wether you are able to use a standard public transformation file, or if you are using a customised private transformation. 

Customising existing Public Transformation files is the most popular option when it comes to updating a stream to working with your requirements. This process basically involves copying the public transformation in to a new private transformation and then customising. Please note writing a completely new or bespoke transformation file is detailed in [this page](/creating-streams/transformations/writing-a-transformation.md).

### Process

The following steps are relative to the HighCohesion control panel:

1. Click on the [Transformations](https://control.hico.io/resources/transformations) link from the left hand menu
2. Click on the "[Public Transformations](https://control.hico.io/resources/private-transformations)" button at the top right hand side of the page. 
3. Locate the existing transformation that you would like to customise and then click on the View link on the right side. 
4. Copy (`ctrl + c` or `cmd + c`) all of the JSON transformation data that is shown in the "Content" box. 
5. Go back to the [Transformations](https://control.hico.io/resources/transformations) link from the left hand menu.
6. Click on the pink "Create Private Transformation" in the top right side of the page. 
7. This then shows the new transformation form, in that form complete the following data:
   1. **Title** - Enter a relative title for the transformation. 
   2. **Source** - Select the destination system from the dropdown list.
   3. **Destination** - Select the destination system from the dropdown list. 
   4. **Data Type** - Enter the main data type for the transformation, e.g order or shipment or customer etc
   5. **Content** - Paste (`ctrl + v` or `cmd + v`) in the transformation data that was copied in step 4 above. Then either save and customise later, or customise before saving. 
8. Once saved you will be able to use your new private transformation with your own customisation in it.

{% hint style="info" %}
For a full tutorial on how transformation logic is built in the HighCohesion system, [follow this link](/creating-streams/transformations/writing-a-transformation/example-1-order-file.md).
{% endhint %}