My latest project - the Coal-Miner's Daughter dress - had a convertible collar, so I took the opportunity to take a few step-by-step photos and add another sewing tutorial to the files. A convertible collar can be worn either open or buttoned, hence the name, and it is commonly seen on blouses and shirtdresses.
I think it is more feminine than a shirt collar with a stand and it sits flatter around the neckline when open, but I do love a good collar and stand too!
The method I'm describing is for a neckline with front neck facings but no back neck facings - so the back neckline requires neatening. There is no handsewing involved and everything is sewn by machine - yay!