Select individual large branches that are declining or badly placed, saw one or two of these out per year or less. Leave the rest mostly untouched.

Removing entire branches will generally not excessively invigorate tree. You can probably safely remove a third of the canopy, particularly if your goal is to reduce height. It is very likely that the apple is not nearly as fireblight susceptable as your pears unless it has suffered in the past.

Fireblight is a bacteria that grows/infects from the bloom. the bacteria becomes attached during your blossoms and multiples it's growth down the limb from there. Pruning wont create blight but you can spread the bacteria if you cut through a blighted limb with out sterilizing your tool.

Thank you bboy, harvestman, and turtleman for your reply.
Do you have any idea about how much they charge for prunning if I call professional tree service people?

If it is a standard apple tree, it is probably going to cost more in maintenance than the fruit is worth.
What rootstock is it on?
If the tree is in excess of 20 feet tall, you probably have a standard.
Believe me, for us folks in the Suburbs or smaller Towns where you have to get rid of pruning branches, it gets costly. Also, to spray a tall tree is an increased risk of 'spray drift'........... a very hot potato issue if you live next to granola types.
personally, if the tree was a Standard and I had it in my yard, I'd be making firewood.
Apple wood burns nice and slow and smoulders for hours in the wood stove. Great firewood.
If you do decide to keep it, I'd prune it in August. Summer pruning is more dwarfing on a larger tree.

I LIVE IN THE DAYTONA BEACH AREA,WHERE CAN I BUY A HONEYBELL ORANGE TREE ? I CAN NOT FIND ANYONE WHO SELL'S THEM AROUND HERE.

What Boizeau said.

I would suggest removing the tree, particularly if it is a standard, (not on dwarfing rootstock) and buying a well-started tree from a good, reputable nursery. In two or three years you could be eating excellent fruit from it.

There are excellent discussions here on the different approaches to pruning apples- vase or central leader, and so on. Your county extension agent can point you to good material too.

Expect to have to control codling moth, at the very least.

If fireblight is an issue you might want to consider a tree that is naturally blight resistant. I believe Empire is one; I have a Liberty that seems untroubled. Same for cedar apple rust.

The connection between fireblight and pruning is two-fold. Pruning active fireblight probably can spread the bacteria, so real caution is needed; dormant pruning will stimulate new growth in the spring, and that new growth is more susceptible to infection.

Good luck,

Mark