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# Exclude and Remove codes from Concept Set
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This page is a continuation of [Create concept set using standard-code descendants](/working-in-the-sandbox/which-tools-are-available/atlas/detailed-guide/how-to-define-a-cohort-in-atlas/concept-sets/selecting-descendants-for-a-concept-set-in-atlas.md) tutorial.
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Once you have created a Concept Set, you can exclude or remove codes using the **Concept Set expression** page or the **Included Concepts** page.
### Exclude codes
The following example shows how to exclude codes using the **Included Concepts** page.
* Select the **Id** column check box on the left for every code you wish to exclude. In the example below we have clicked all shown codes.
* Scroll down the page, select the **Exclude** check box and click the **Add to Concept Set** Button.
* You can see the excluded codes on the **Concept Set Expression** page; they have their **Exclude** column checkbox selected. In the example below, the number of concepts shown in the **Included Concepts** tab was reduced to 96.
### Remove codes
The following example shows how to remove codes using the **Concept Set Expression** page.
* Select the **Id** column check box on the left for every code you wish to remove. In the example below we have clicked all shown codes except for Asthma and Allergic asthma.
* Scroll down the page, and click the **Remove Selected** Button.
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If you remove excluded standard code descendants, then these codes will become part of the Concept Set again.
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