Changing the duration of a Single Step

Liz_Connors_(sunvalleyfoodadmin_-_(deleted))

How do you go about changing the duration of a workflow step at the Database level, such that the change appears in the Map View etc for that workflow as well the step duration being amended in the relevant users task list.We DO NOT however want to amend any other steps in the workflow or the overall due dates/durations, simply ones for that specific step