Currently when moving a workout this will trigger all other workouts to move as well. To move your workout back to it's original routine you can do this by:
-Clicking on the "Workouts" tab -Click "Change Plan" under Your Plan
-Choose your chosen plan -Press "Select Program"
-Choose your experience level and how often you wanted to train
-Scroll and choose the correct workout to begin
-Choose your chosen start date
This will then move your workouts back into their original rhythm.
Please note if you restart the workout this will cause the stars to be removed, however your workouts will still be marked as completed.