My Grandsons room has 2 large closets, while my Grandaughter has only 1.Closets are back to back. I would like to remove his door,and close in the plaster wall.The walls are plaster,can I use drywall? In Grandaughters room,would like to cut in a doorway in the plaster wall and add a new door. How do I go about doing this, never worked with old plaster/lath walls before?

remove a door, patch opening, cut in and add a door in a plaster wall