You can add respondents to any active FlourishDx survey until you have closed the survey.
Login to you Admin Dashboard.
Navigate to Surveys > [SurveyType].
Click on the survey you wish to add respondents to.
Click Add Respondents button in the top right of page.
Select the respondents either individually, or using the filter tool. You can select all users by checking the box top left next to Name.
Once your selection is finished, click Add Users.
Click Confirm. This will send the survey request to the selected users.