A patentee, whether of the whole or any sectional interest therein, may, on payment of the fee required by law, make disclaimer (give up all or part of the owner's rights to enforce claims) of any complete claim , stating therein the extent of their interest in such patent. Such disclaimers are required to be in writing and recorded in the USPTO, and are considered as part of the original patent to the extent of the interest actually possessed by the disclaimant and by those claiming under him. Any patentee or applicant may disclaim or dedicate to the public the entire term, or any terminal part of the term (from a certain point in time through the projected end of the entire term), of the patent granted or to be granted. There are two types of disclaimers: a statutory disclaimer and a terminal disclaimer.
Source: U.S. Patent and Trademark Office.