> For the complete documentation index, see [llms.txt](https://docs.keyfax.biz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.keyfax.biz/product-suite/admin/databox-expressions/text-expressions/replace.md).

# Replace

Returns a string in which a specified sub-string has been replaced with another substring.

<table data-full-width="false"><thead><tr><th width="267">Expression</th><th width="245">Databox Value</th><th width="225">Result</th></tr></thead><tbody><tr><td><code>Replace('B','b')</code></td><td>The Big Brown fox</td><td>The big brown fox</td></tr><tr><td><code>Replace('NOTE:','!!! IMPORTANT NOTE !!!')</code></td><td>NOTE:</td><td>!!! IMPORTANT NOTE !!!</td></tr></tbody></table>