A white wine can be made from red grapes, and a red wine can be made from white grapes.
The first phrase is true, but the second is not. The juice of all grapes, red and white, is almost colorless (with a few rare exceptions). If the juice from red grapes is fermented without the red grape skins, white wine can be made. (One example is a Champagne made from Pinot Noir grapes). But if the skins are white and the juice is necessarily white, a red wine cannot be made.