I really should know the answer to this, but I don't. I haven't encountered this yet and will definitely ask at work tomorrow.
Are you talking about Rack items you bought online? My assumption is that these items still have to be returned to a full-line Nordies but I don't know for sure. I recently bought some items online (from both the regular Nordies and Rack) and all the items were on the same packing slip... so that leads me to believe they need to be returned to full-line Nordies. I think they all come from the same warehouse.
But... I don't know. So I am just thinking out loud and not being helpful at all.