No, it's currently not possible to modify the eligibility requirements on a live study.
In order to update the eligibility on a study we normally recommend that you close your current version of the study and review the remaining participants if possible.
Then, duplicate the study and update the eligibility requirements. You can then publish this study.
To avoid participants who took the initial study taking it again, you can use a Previous Studies screener to exclude them - before you can do this, you'll need to make sure that the first study is complete and that you have reviewed all submissions.