To cancel the 49 Euro Deutschland-Ticket subscription, you need to do so by the 10th day of the current month to avoid paying for the next month. The exact cancellation procedures may differ from provider to provider, but for Deutsche Bahn, the most direct way to cancel the 49-euro ticket is via the subscription portal. If you purchased the ticket through another platform, such as the Deutsche Bahn website, DB Navigator app, or a local public transport association's online platform, visit the respective platform to cancel your subscription.