Question

After the enzymes amylase breaks down a starch molecule, it can

Answer 1

      Generally speaking, enzymes (which amylase happens to be) do not undergo any permanent structural change while carrying out their function. Some do exhibit transient conformational change during a reaction, but upon completion regain their original form.  

So your initial assumption is correct: once amylase has finished catalyzing the breakdown of starch into less complex sugar molecules, it moves on and repeats the process over and over.