This is a cracked sink that is embedded inside a countertop. To change this sink, I had to call in the countertop specialist, to prise away the countertop, to gain access to the sink. Then the vertical and horizontal width measurements have to be taken, to search for a new sink with matching measurements.
If the new sink is not a good fit for the countertop, it simply can not be fixed. This is the con and disadvantage of the countertop with a fixed opening for the sink.

After dismantling the countertop, the vanity cabinet below has no structure to help it to be attached and so it starts to fall apart, as shown in the photo below. If you have a carpenter at hand, he might be able to do the necessary work to fix the falling cabinet.

Even if you repair the cabinet, there is the primary issue of the replacement sink, which must be a very good fit for the countertop.
This is a solution to the problem of having a sink to fit the countertop, and repairing the broken cabinet
To eliminate the problem of sink sizes, and broken cabinet, we can use the standalone cabinet with its very own sink resting on top of it. This way, there is no need for a countertop and fitting sink. Plus, the detached cabinet can be dismantled and discarded.

Once a sink is dismantled, its attached tap is usually rendered un-useable. A new tap has to be bought for attachment to the new sink.
There is so much trouble and expense to replace a cracked old sink.
Replacements are:
- New sink.
- New tap.
- New vanity cabinet.

This video shows a plumber removing a cracked sink. The owner managed to buy a new sink with the exact measurements.