Yew can be pruned and will respond well. If you have cold winters in your area, I'd leave it until spring, though. New growth at this time of year would be affected by frosts.

I agree just give it an appropriate prune in the spring.

I've seen Yew pruned right down at Wisley, which, along with Kew , is our main, centre of gardening and horticultural expertise. This is to re establish control over the tree. After all they are the main subjects for topiary and can take a lot of clipping and pruning as well.