Thank you for your ideas. You have helped me a lot with this!
I have another question:
The two layouts, which I have created, do I need for my reminders. Do you think that the change of the layouts will also be possible if I also want to print on the RequestPage in the filter "No." several reminders?
I am afraid that this might not work. However, I work with dunning runs and sometimes dun 1000 customers per month. Therefore, the layouts have to to changed automatically. I have a flag that makes clear which layout should be used. This flag is a boolean field on the Issued Reminder Header.