Can I apply a code to my existing subscription? March 07, 2019 19:13 Updated Follow Unfortunately, there is no way to apply a code to an existing subscription, as codes can only be applied during checkout. Related articles My Shyn Sonic Toothbrush was lost or stolen. Can you help? How do I know when it’s time to charge the battery? Can I cancel my order or make changes after placing it? I didn’t get my order confirmation email. What should I do?