37 CFR § 42.221 - Amendment of the patent.
(2) Scope. A motion to amend may be denied where:
(ii) The amendment seeks to enlarge the scope of the claims of the patent or introduce new subject matter.
(3) A reasonable number of substitute claims. A motion to amend may cancel a challenged claim or propose a reasonable number of substitute claims. The presumption is that only one substitute claim would be needed to replace each challenged claim, and it may be rebutted by a demonstration of need.
(1) The support in the original disclosure of the patent for each claim that is added or amended; and
(2) The support in an earlier-filed disclosure for each claim for which benefit of the filing date of the earlier filed disclosure is sought.
(c) Additional motion to amend. In addition to the requirements set forth in paragraphs (a) and (b) of this section, any additional motion to amend may not be filed without Board authorization. An additional motion to amend may be authorized when there is a good cause showing or a joint request of the petitioner and the patent owner to materially advance a settlement. In determining whether to authorize such an additional motion to amend, the Board will consider whether a petitioner has submitted supplemental information after the time period set for filing a motion to amend in paragraph (a)(1) of this section.
(d) Burden of Persuasion. On a motion to amend:
(1) A patent owner bears the burden of persuasion to show, by a preponderance of the evidence, that the motion to amend complies with the requirements of paragraphs (1) and (3) of 35 U.S.C. 326(d), as well as paragraphs (a)(2), (a)(3), (b)(1), and (b)(2) of this section;
(2) A petitioner bears the burden of persuasion to show, by a preponderance of the evidence, that any proposed substitute claims are unpatentable; and
(3) Irrespective of paragraphs (d)(1) and (2) of this section, the Board may, in the interests of justice, exercise its discretion to grant or deny a motion to amend only for reasons supported by readily identifiable and persuasive evidence of record. In doing so, the Board may make of record only readily identifiable and persuasive evidence in a related proceeding before the Office or evidence that a district court can judicially notice. Where the Board exercises its discretion under this paragraph, the parties will have an opportunity to respond.