The permits patent owners to move . However, attempts to amend claims have been largely unsuccessful to date, and some of the hurdles patent owners face are not set forth in the rules. We first review statistics and relevant case law to survey the development of motion to amend practice, including the ¹ decision from earlier this year, the first decision to grant a motion to amend after guidance provided by a few notable Patent Trial & Appeal Board (Board) and Federal Circuit decisions. We conclude with recommendations and practice tips for a successful motion to amend. Motions to amend can be grouped into two buckets: (1) motions seeking cancellation of claims; and (2) motions seeking substitution of pending claims with amended claims. Regarding the first category, as of May 19, 2016, the Board has granted all 32 filed motions that sought cancellation of claims. The second category, however, has faced nearly the opposite result—of the 146 motions to amend as of May 19, 2016, the Board has only granted four: ², two for related IPRs³, and . These four decisions are discussed below chronologically with pertinent case law. Earlier this year, the United States Patent and Trademark Office (PTO) released (“The 2016 Amendments”) that took effect on May 2, 2016. The 2016 Amendments do not make any changes to the rules for motions to amend, but in response to comments, the amendments indicated that the PTO would “further consider ways to promote uniformity in the requirements for a motion to amend, such as by designating opinions precedential, issuing a standing order setting forth what requirements govern a proceeding for motions to amend, or other means.” Thus, for now, the PTO has left patent owners to sift through Board and Federal Circuit decisions to understand the state of motion to amend practice. The 2016 Amendments address two important decisions that have contributed to the development of motion to amend practice: (1) ⁴ and (2) ⁵. In the 2013 decision, the Board explained that the patent owner—not the petitioner—bears the burden to show a “patentable distinction over the prior art of record and also prior art known to the patent owner.” The 2016 Amendments explain that the ultimate burden of persuasion always remains with the patent owner. However, the burden of production shifts to the petitioner once the patent owner sets forth a case of patentability of narrower claims. In response, the petitioner may explain why the patent owner did not make a case, or may attempt to rebut that case by addressing the patent owner’s evidence and arguments and/or by identifying and applying additional prior art. The patent owner can address these arguments and any new references in its reply. Between the and decisions, the Board granted the and motions to amend. The May 20, 2014 decision in was notable as the first in which the Board permitted amendment of claims in an IPR. The motion was unopposed, but the Board still confirmed that (1) the proposed substitute claims were narrower than the original claims, (2) the motion set forth support for the amendments in the specification, and (3) demonstrated that the claims were patentable over the prior art in general. On December 30, 2014, the Board granted, in part, two motions to amend in two related IPRs filed by petitioner . The facts of the decisions are somewhat atypical given that the patent owner did not submit a declaration in support of the claim amendments and used dependent claims as the basis for the amendments. Additionally, in its opposition, the petitioner did not challenge written description support, or identify a reference that taught certain limitations of the claims. In the 2015 decision, the Board provided clarification by expounding on what the phrases “prior art of record” and “prior art known to the patent owner” mean from the Idle Free decision. To demonstrate patentability over the “prior art of record,” the patent owner needs to distinguish over (a) material art in the prosecution history of the patent, (b) material art in the current proceeding, and (c) any material art of record in any other proceeding before the Board. To demonstrate patentability over “prior art known to the patent owner,” the patent owner must distinguish over any art “provided in light of a patent owner’s duty of candor, and any other prior art or arguments supplied by the petitioner.” While not addressed in the 2016 Amendments, after and the Federal Circuit decided the appeal in 2016, requiring the Board to reconsider its denial of the patent owner’s motion to amend. On whether the patent owner satisfied its duty of candor when demonstrating patentability, the Federal Circuit held that the patent owner’s simple statement that the claims were patentable over the prior art known to it but not of record the patent owner’s duty even though it did not substantively discuss any of those references. The PTO conceded on appeal that given the clarification in —issued after the Board’s decision in the IPR—the Board’s decision finding that the patent owner’s statement was insufficient for failing to address any specific references that were known to it but not of record was too aggressive.