A crabapple IS a regular apple tree.........just a different type of one. There are several species of crabapples but only one species of orchard apple, Malus domestica. Since you can't change the species of an existing tree, your crabapple will always remain a crabapple. If you want a regular or orchard/grocery store apple, you will need to purchase and plant a cultivar of Malus domestica.