I've finally found the exact sentences, so I'm putting here a new answer instead of the yesterday's one.
As it's written in official materials of Copernikus' Museum in Frombork, Poland, such corrections were done simply by striking out some parts of the text and it happened only with something like 8% books that survived until recent times. It was their owners responsibility to delete those fragments, so it's no wonder that many of them didn't want to do that. What's interesting, for Italy the percentage is around 60%, while for Spain and Portugal, which were strongly Catholic countries, none of the books were changed. The process of deletion and changes looked f.e. like here, at the copy kept in Peabody Library:
Thankfully, one of the copies of second edition (1566) is among the highlights of University of Rochester libraries, which provided a nice description to all changes, including the most famous ones, from 1620. I'll quote only the fragments connected with Inquisition changes. For more informations and photocopies of changed pages, check the link to official page of library for an article with full description of this particular copy
In 1616, the Inquisition placed De revolutionibus on its Index until
corrected -- Decree XIV. In 1620, in Decree XXI, the required
corrections were officially announced. This is an extraordinary
measure since for very few books did the Index specify the type of
changes to be made. The ten emendations were designed to make
Copernicus' book appear hypothetical and not the description of a real
physical work. One may wonder why the Church took 77 years to react
against an astronomical treatise whose content seriously challenged
the traditionally accepted idea that placed a static earth in the
center of the universe. One of the reasons is that numerous scientists
only viewed the treatise as a useful manual to calculate planetary
positions for any conceivable time, emphasizing, however, the
hypothetical character of Copernicus' main thesis. Indeed, the first
edition of 1543 included the infamous anonymous foreword, in fact
written by Andreas Osiander, containing the following words: "these
hypotheses need not to be true nor even probable."
We are going to show some examples of how the recommendations of the
Inquisition were faithfully applied in this second edition of the
treatise. Passages from the specific recommendations of Decree XXI are
provided in translation and in italics. After each recommendation, one
can observe how it was reflected in the text itself.
Therefore, with these recommendations, let those who have some
diligence approach the judgment of this emendation, which is as
In the preface near the end:
Delete everything from "perhaps" (Si fortasse) to the words, "my work"
(hi nostri labores) and adjust it thus, "my work and those of others"
Here we include Professor Edward Rosen's translation of this deleted
passage from Copernicus' preface -- a dedication to Pope Paul III:
"Perhaps there will be babblers who claim to be judges of astronomy
although completely ignorant of the subject and, badly distorting some
passage of Scripture to their purpose, will dare to find fault with my
undertaking and censure it. I disregard them even to the extent of
despising their criticism as unfounded. For it is not unknown that
Lactantius, otherwise an illustrious writer but hardly an astronomer,
speaks quite childishly about the Earth's shape, when he mocks those
who declared that the Earth has the form of a globe. Hence scholars
need not be surprised if any such persons will likewise ridicule me.
Astronomy is written for astronomers. To them my work too will seem,
unless I am mistaken, to make some contribution also to the Church, at
the head of which Your Holiness now stands."
In chapter 5 of Book I, folio 3:
From "Nevertheless, if we examine more carefully," correct it to
"Nevertheless, if we were to examine the matter more carefully, it
makes no difference whether the earth exists in the middle of the
universe, or away from the middle, as long as we judge that the
appearances of the heavenly motions are saved. (Si tamen attentius rem
cosideremus, nihil refert terram in medio mundi, vel extra medium
existere, quoad salvandas caelestium motuum apparentias existimemus).
Here we include the original sentence that has been deleted:
(videbitur haec quaestio nondum absoluta, & id circo minime
contemnenda): "it will be apparent that this problem has not been
solved, and it is by no means to be disregarded."
On folio 10, at the end of the chapter, delete these last words: "So
vast, without any question, is the divine handiwork of the most
excellent Almighty" (Tanta nimirum est divina haec Opt. Max. Fabrica).
Certainly, the Inquisition thought that this passage clearly
identified the design of the Creator with the heliocentric system,
which is graphically described in the famous woodcut inserted in the
previous page of the treatise.
In chapter 11:
The title of the chapter (De triplici motu telluris demonstratio: On
the explication of the three-fold Motion of the Earth) should be
adapted in this manner, "On the Hypothesis of the Three-fold Motion of
the Earth and its Explication." (De hypothesi triplicis motus telluris
eiusque demonstratione). The inscription circa telluris axem is
probably a stylistic suggestion to replace the printed version circa
axem telluris. Stylistically, a genitive such as telluris is normally
placed between the preposition and the noun. Furthermore, we also note
that the first edition includes a comma after telluris. One may wonder
whether the reader of our copy wished to emphasize, and clarify, that
telluris should only modify axem.