I understand you want to remove the existing translation for some of your posts/pages. Is that right?
If that's the case, you can go to your WordPress dashboard → Pages (in case you want to remove the translated pages) and then switch the language using the admin language switcher, as seen in the attached screenshot.
After that, you can select the pages you want to delete and move them to the trash. Then, make sure to go to the trash and empty it.
Hope that helps, and let us know if you have any other questions. We would be happy to assist further.