Can I check in without a reservation?

Yes, you can also check in without a reservation at a free, non-reserved seat. Simply enter the coach and seat number manually and complete the check-in process.

Alternatively, you can use the QR code to determine the coach and seat number as follows:

1. Start check-in in DB Navigator and open the camera by clicking on the QR code icon (you may have to agree to the use of your camera) 
2. Scan the QR code. You will find the QR code on a sticker, which is usually attached to the backrest of the front seat or in the wall area of the window. If the sticker shows two QR codes, use the one on the right. 
3. The coach and seat number will be determined via the QR code. Click the button “Check in now” to complete the Komfort Check-in. 

Read more about this here