The message
from John Rumm contains these words:

If it is rebar, then you can get rebar cutting masonry bits that ought
to do the job. (Just positioning the hole in a different location will
probably help you miss the rebar).

Yes, but the holes already drilled will let in water, the rebar will
rust and the concrete post will start to disintegrate. Any holes drilled
need filling pdq. Any others drilled in the post might cause a long term
problem even if they don't hit the rebar.

--
Roger Chapman