# Add built-in normalizer to existing indices

**URL:** <https://discuss.elastic.co/t/add-built-in-normalizer-to-existing-indices/333360>\
**Category:** Elasticsearch\
**Created:** [May 13, 2023, 5:47pm UTC](https://discuss.elastic.co/t/add-built-in-normalizer-to-existing-indices/333360 "2023-05-13T17:47:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![NishuGoel](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nishugoel/32/120993_2.png) [@NishuGoel](https://discuss.elastic.co/u/NishuGoel)\
**Post date:** [May 13, 2023, 5:47pm UTC](https://discuss.elastic.co/t/add-built-in-normalizer-to-existing-indices/333360/1 "2023-05-13T17:47:57Z")

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Hi there,  
I was going through the documentation where it says for some mapping parameters, we CAN update the existing index using PUT index/\_mapping.  
"normalizer" being one of those parameters - [Update mapping API | Elasticsearch Guide [8.7] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-put-mapping.html#updating-field-mappings)

But it seems like we cannot even update the normalizer on an existing index using the putMapping API?

I am trying adding normalizer directly to a field, but `Cannot update parameter [normalizer] from [null] to [lowercase]`

Should I have to reindex the whole data even for adding normalizer to existing index mapping?

Appreciate an answer on this, thanks!

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<div class="post-metadata">

**Author:** ![RabBit\_BR](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rabbit_br/32/82261_2.png) [@RabBit\_BR](https://discuss.elastic.co/u/RabBit_BR)\
**Post date:** [May 15, 2023, 8:52pm UTC](https://discuss.elastic.co/t/add-built-in-normalizer-to-existing-indices/333360/2 "2023-05-15T20:52:09Z")

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Hi @NishuGoel

I couldn't find the documentation to confirm my answer, but in these cases of editing existing fields, the correct option is to [reindex](https://www.elastic.co/guide/en/elasticsearch/reference/7.17/docs-reindex.html) the index until, if it is possible to change the existing field, you would have incorrect data already indexed.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [June 12, 2023, 8:52pm UTC](https://discuss.elastic.co/t/add-built-in-normalizer-to-existing-indices/333360/3 "2023-06-12T20:52:33Z")

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