How to refund all current active subscriptions

Hello, we're going to shutdown the app and remove it from the AppStore. As we have renewable subscriptions, some users have subscribed and will have active subscription by the date we'll shut down the app. Is there any way to automatically or manually refund all users the amount they paid for active subscription ? We know StoreKit's Transaction class has beginRefundRequest(in: ) but we'd like to not rely on user's action and perform the refund by our own.