> For the complete documentation index, see [llms.txt](https://docs.tonic.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tonic.ai/textual/dataset-configure-redaction/textual-datasets-synthesis-options/synthesis-replacement-values.md).

# Providing specific replacement values

For all entity types, you can:

* Map original values to replacement values.
* Provide a constant value to use to replace all of the original values, except for mapped values.

<figure><img src="/files/uzqfVQWzc81bBxgiKwqb" alt=""><figcaption><p>Synthesis options that apply for all entity types. Include mapping specific values and providing a constant value.</p></figcaption></figure>

## Mapping original values to replacement values

You can map specific original values to specific replacement values.

For example, for the Given Name entity type, you might indicate to always replace John with Michael and Mary with Melissa.

For original values that are not in the mapping:

* If you also provid a constant value, then Textual uses that value.
* Otherwise, Textual selects the values.

### Providing the mapping

In the text area, provide a JSON object that maps the original values to the replacement values. For example:

```json
{
  "French": "German",
  "English": "Japanese"
}
```

With the above configuration for the Language entity type:

* All instances of `French` are changed to `German`.
* All instances of `English` are changed to `Japanese`.
* For all other language values, Textual selects the replacement values.

### Values are case-insensitive

The values are case-insensitive.

For example, if you specify `"John": "Michael"`, then Structural also replaces `john` with `michael` and `JOHN` with `MICHAEL`.

### Leading and trailing punctuation is ignored

Structural ignores leading and trailing punctuation.

To continue the example of `"John": "Michael"`, Structural also replaces `'John'` with `'Michael'`.

## Providing a constant replacement value

You can provide a single constant value to use to replace all instances of the entity type. For example, you might replace all bank numbers with "0000000".

In the **Constant Value** field, provide the value to use.

When you provide a constant value, Textual ignores other [entity type-specific synthesis configuration](/textual/dataset-configure-redaction/textual-datasets-synthesis-options/synthesis-options-for-specific-entity-types.md).

However, Textual does respect any [mappings of original values to replacement values](#mapping-original-values-to-replacement-values).


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