How to modify a user-defined list style in Microsoft Word 2016

1. Click Format > Bullets and Numbering... > List Styles
2. Select the style you want to modify and click Modify... . You can only modify user-defined styles.
3. Update style
4. Check Add to template. If you don't check this checkbox, your changes will only be applied to the current document else your changes will be applied to the template and will reflect not only to the current document but also to new documents.