Train ticket not saleable if I change plans?

Insufficient information. Rail provider? Ticket seller? Which fare exactly? Name on ticket?

If first both Deutsche Bahn cancellation depends on fare type (two different saver optons), see DB fare overview. Reselling not possible if name on ticket.

Check information at ticket seller and / or rail provider.

Yeah, check with the rail provider first. in case you might change plans its always better to take flexible option or book cancellation insurance if available.

Hey, @Markk
Your suggestion is absolutely Right. If your name on the ticket, you can't sell it.

If you bought a "self-print" ticket the on the internet, it will have your name on it, so nobody else can use it. The reason it has a name on it is to stop you printing two copies and two different people using it.

If you bought it in person at a station ticket machine or manned counter, it will not have a name on it and anybody can use it. It is like cash, you can give it to anybody. However you still need to find someone who wants to go from Frankfurt to Paris on the date in question.