Very carefully.

Contacting a local mason or talented handyman may help too.

You are out of your depth. Call in a contractor.

Learn about 45s and flexible angles for rigid piping. And call a contractor.

Here's the info on removing bricks without damage to be reused.

Unscrew the vent and cut the brick with a masonry blade in a circular saw or grinder. Salvage the cut outs to fill the old hole. It'll be a tricky one.

Have the contractor check if it would be feasible to use an Offset Range Hood adapter.

They have saved my butt a few times when dealing with bricked in vents. They come in different configurations.

I cut a new hole in my double-layer brick wall to install a new door, and it is not a job for the faint of heart. A concrete saw with a 14" blade works great, but its heavy and hard to handle on a vertical wall cut (much easier on a sidewalk or driveway). And don't forget - its also spinning at a rate that would take a huge chunk out of your hand, arm, or leg before you get it back in control. I would not use a concrete saw on this type of job.

If its only a brick facade (one layer), for a hole of that size you could use an angle grinder with a masonry blade to cut out all the mortar (cutting from both sides because the blade is only about 4 1/2" diameter), and then pull out the bricks. Then you have to reassemble it all with the new hole in the right place, and use the right type and color of mortar so that the patch is not so evident. You also need a steel lintel to go across the top to hold up the row of bricks, although you may be able to use the one that is already there. The renovation contractor for my kitchen did it right and it looks good, but it was not a simple job.

Bruce

Along the same lines as suggested by MULE , on a new home build the cabinet installer ended up off-centre to the vent. So, my HVAC installer lined the cabinet over the hood with sheet metal.

Get a mason, remove the brick (there no weight above it), move your vent and re-brick using existing if it can be used, if not you can purchase this brick, it's called Red Vertical Score brick should be available at most brick selling outlets and make a nice neat repair. It's a very simple project.

Good luck.