Under the European Patent Convention (EPC), a petition for review is a request to the Enlarged Board of Appeal of the European Patent Office (EPO) to review a decision of a board of appeal.
[1] Its purpose is not to obtain a reconsideration of the application of substantive law, such as points relating to patentability.
[1][2] The petition is a restricted form of judicial review, limited to examining serious errors of procedure which might have been committed by the Legal or Technical Boards of Appeal, prejudicing the right to a fair hearing of one or more appellants.
In the later case, the petition must be filed "within two months of the date on which the criminal act has been established", but no later than five years after notification of the Board of Appeal's decision.
[1] However, a procedural error marring the appeal proceedings does not, by itself, suffice to guarantee a successful petition.
[8] This first stage is "a quick screening process to be conducted by a three-member panel of the Enlarged Board in order to reject petitions which clearly cannot succeed.
[8] To reject a petition as clearly inadmissible or unallowable, the three-member panel has to reach the decision unanimously.