Substitute for Pastry Flour from Limited Traditional and Alternative Flours
You can sift the whole flour to make it white flour.

Originally, millers used stones to grind the grains. The whole grain was completely ground, and all of its parts were mixed in the process. Wealthier people could sift the flour to discard the husks. Poor people ate whole flour bread.

Nowadays, flour is gotten from roller mills, where first the husk is removed, then the germ, and then the endosperm is ground. When you get whole flour (unless the miller says it's stone milled), they've put together the outer part and the endosperm. You can sift it to separate them.

So, in both cases, sifting the whole wheat pastry flour will make you get white pastry flour.