You can edit a survey if it has not been previously distributed. If the survey has been emailed or posted to social media, then you cannot edit anything within the survey. You can, however, decide to email it or post it to a different social media site that you have not previously done.
If your survey or poll status on the My Surveys tab of the Survey List page is In Progress, then you can edit any details within the survey. Select the appropriate survey or poll and click on the Edit button at the top of the grid.