Change the Blend

After you've created a blend (and it's still live), you can change the number of steps in the blend by going to the Object menu and choosing Blend>Blend Options (or double-clicking the Blend tool in the Toolbox). In the dialog, change the number of Specified Steps and the blend will update. An even quicker way is to check the Preview box at the bottom of the dialog, and use the Up and Down Arrow keys for an instant update.