However, the use of the product must obtain the permission of the prior patentee.
For example, apply for a patent for the bench, you add a backrest to the bench, and you apply for a patent for the chair.
Then, if you want to use and sell chairs, you must get permission from the patentee of the bench.
Of course, the patentee of the bench must get your permission if he wants to use and sell the chair.
It depends on how the benefits are distributed.