You can ONLY sell tickets that you have purchased. So, as long as you have a purchase receipt, and the tickets are (or will be) transferrable they can be sold on CashorTrade.
It's OK to sell tickets you own and have a receipt for, but don't have in your possession yet ('Not In Hand', or not transferrable yet) as long as you are certain you will have them on the date you provide when creating the listing to sell the tickets (the 'In-Hand Date'). The 'In-Hand Date' you provide is the beginning of your delivery window to complete the sale. If your tickets haven't sold and the 'In-Hand Date' changes, you may update the 'In-Hand Date' by deleting your listing and creating a new on with the correct 'In-Hand Date'. If your tickets have sold and the 'In-Hand Date' changes, your buyer may request a refund and could considered a 'Dropped Sale' since it would be failure to deliver the tickets as explained in the listing.