How can I use a promo code if I already use the product?

I’m already using KLARA Bank Reconciliation, and now I’ve received a promo code from my bank. How can I make use of the offer?  

If you’ve already activated KLARA Bank Reconciliation, you’ll need to deactivate the widget in the Widget Store by clicking on “Log out”. Once the subscription has expired, you can reactivate it by entering the promo code.