How do I model an open pocket?

If I make a model of a shirt with multiple pockets of which some are open. How to I retopologize it. I am not in a game industry so I am not confident in my way of doing it. I generally make the shirts in marvelous designer then I retopologize everything either in Maya or maybe zremesh in zbrush and unfold. But my pockets are floating. They are not welded to the shirts. Is it right? If it's closed I could easily coverup it in baking. It's a simple question but I don't know how to...