[Resolved] Want to change my standard language without effect on SEO. How to do it?

Problem:
You want to change the default language of your site from English to Dutch without affecting your SEO performance. You are also looking to automatically redirect visitors from the Netherlands to the Dutch version of your site.
Solution:
To change the default language while maintaining SEO, you can adjust the URL structure settings in WPML. If your current URL structure is:

https://your-site.com/ → English 
https://your-site.com/nl/ → Dutch

After changing the default language, it will look like:

https://your-site.com/ → Dutch
https://your-site.com/en/ → English

To keep the language folder for the default language, enable the option "Use directory for default language" in WPML → Languages → Language URL format. This will preserve the /nl/ path for Dutch, while the English version will include /en/. Note that changing the default language will impact the URL structure for at least one of your languages.
For more information, visit Directory for Default Language.
If your goal is to redirect visitors from the Netherlands to the Dutch version, refer to the supported methods here: Automatic Redirect Based on Browser Language.

If this solution does not apply to your case, or if it seems outdated, we recommend opening a new support ticket. We also highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. For further assistance, please visit WPML Support Forum.