Best thing is-why ask here?-to check again by starting a new RES and what it then says about exchange/cancel or whatever. Or even what is says in the mail you got with that ticket linked to. May also depend on what you exactly RES

I'm looking for someone's experience to see if it can help me, nothing more friend. That is the purpose of the forum.

In general seat reservations are not refundable. You will need to ask OBB to consider your case but if it’s only a few euros do as mcady says and just book new ones. If you reserved sleepers then refunds can normally be given but there are heavy cancellation fees!