There is always a change that content contains mistakes, or that it is not up to date anymore. That means that you have to update your drill. 

If you do this, it is important to check whether the update needs to influence the proficiency score of the learner. This is the case if the old content is not up to date or not correct anymore. If the update is only about correcting a spelling mistake, for example, it does not have to influence the proficiency score of the learner. 

If you correct the spelling mistake in the editor, you can release the drill and the correct version will be immediately live for the learners. 

If you want the proficiency to be influenced, select the option 'Reset proficiency for this item'. The proficiency of the learner will drop and they will need to return to the drill faster, to make sure their proficiency meets the learning objective. 

After selecting the option to affect the proficiency, you also have to release the drill. The correct version will then be live for the learners to see.