If you have launched your survey, you will not be able to delete any questions. This restriction applies as soon as you launch your survey. The restriction stays in place regardless of whether your survey’s status is scheduled, open or closed.
Launching your survey also disables some of the editing functionality. The disabled functions will appear greyed out when you open the editor for a question, note or page or when you click on the 
actions icon.
If you have launched your survey and find that you need to make a change that cannot be made to a launched survey, you can copy the incorrect survey. This will create a draft version of your survey with all of the editing functionality available. You can then make the required changes on the copy, close the original, incorrect survey and launch the copy.
For a detailed list of the items you can and cannot edit once you have launched your survey, please see our Help article on editing a launched survey.