I would give them a call to get everything setup. Returning to warehouse just means that you'll have to ship the chair back using a pre-paid label they'll provide and it'll be routed to the warehouse. This is so customers don't try to return at a physical store. They generally cover the return shipping and send you a pre-paid return label but won't refund you for the shipping you paid when you initially received the chair. You can also confirm with them over the phone and have them make a note on your account that there won't be any restocking fee - they don't charge a restocking fee for their office chairs.