Note: You can only reuse a fixed length program once it has finished. If you're currently following the program you won't be able to 're-use' it until it's finished. You can reschedule a fixed length program if it's currently in your calendar.
My Purchases should open by default, if not use the menu options to navigate here.
Profile picture -> Billing -> My Purchases.
Navigate to the program in question on this list and click the ... option menu.
You should see the option here to 'Reuse'.
Click this and you'll have ability to select a fresh start date for your program.
Choose the date you want to start the program again and you're good to go. This will not affect any performances you added to the program first time round.
Thanks
FITR