37 C.F.R. § 42.206 – Filing date.

(a) Complete petition. A petition to institute a post-grant review will not be accorded a filing date until the petition satisfies all of the following requirements:
1. (1) Complies with § 42.204 or § 42.304, as the case may be,
2. (2) Effects service of the petition on the correspondence address of record as provided in § 42.205(a); and
3. (3) Is accompanied by the filing fee in § 42.15(b).
(b) Incomplete petition. Where a party files an incomplete petition, no filing date will be accorded and the Office will dismiss the request if the deficiency in the petition is not corrected within the earlier of either one month from the notice of an incomplete petition, or the expiration of the statutory deadline in which to file a petition for post-grant review.