You may be wondering, why would I just make a collar?  One of the best reasons is to add this collar to another high neckline shirt for extra fashion without having to wear two shirts at once.  You can even wear this collar with a low neckline shirt, so the collar stands by itself for a different look.  If you love the look and want to easily pull it off yourself, you're in luck.   The best part is that it takes very little fabric, it can be embellished and it can be put together quickly and easily.  With a high neckline shirt, you can wear it buttoned up or unbuttoned.  I just slip it on the neckline after putting on my original shirt.  If you want to keep the detachable collar more attached to one particular shirt, you can do some gentle hand stitches attaching the collar to the neckline of the shirt.  Just make sure to do your stitching with the collar unbuttoned so you won't have any problems slipping your shirt on and off.