37 CFR §1.525

1. (a)If a substantial new question of patentability is found pursuant to § 1.515 or § 1.520, the determination will include an order for ex parte reexamination of the patent for resolution of the question. If the order for ex parte reexamination resulted from a petition pursuant to § 1.515(c), the ex parte reexamination will ordinarily be conducted by an examiner other than the examiner responsible for the initial determination under § 1.515(a).
2. (b)The notice published in the Official Gazette under § 1.11(c) will be considered to be constructive notice and ex parte reexamination will proceed.