In the Test/Survey Manager, choose the test who's properties you wish to change and use the Edit button. This will display a screen like the one for Creating Tests & Surveys, where the test's properties can be altered and saved.
To delete a Test or Survey, choose it from the Test/Survey Manager and use the Delete button. Aftering confirming the delete action, the test will be removed. Note that the questions within the test will not be deleted as they are stored in the Question Bank.