First, you can edit your recipe by going to sparkrecipes.com and logging in. Then, go to the "My Recipes" tab and select "My Recipe Box." There, you will see your recipes with an option to edit or delete the recipe to the right of the recipe title.
In addition, as long as you didn't check the box to make the recipe public, only you can see it. You can create as many unshared recipes as you wish for your own use without positing it for others. In your recipe box you also have the option to share or unshare each recipe.
I hope this helps!