As it gets closer to November, I generally check the forecast before making decisions like this. If the days will be mild and nights above freezing, go ahead and move it. If not, wait until spring. Either way, first get the new hole ready. Work in compost. Water the hydrangea you are about to dig up. It will help keep the dirt around the roots. If the top is quite large, you might prune it back some or gently tie it up. It will help keep the branches from hitting you in the face when moving it! Move it to the new spot, really pack in the dirt around the roots and base of the hydrangea, mulch, and give it a good soaking. In the spring, be certain it gets a good soaking from periodic rain or water as needed. And, fertilize in the spring.
Thanks for writing!