If applicants do not agree with the finding of lack of unity they can request a review of this finding. This procedure is similar to the protest procedure with the difference that additional fees cannot be paid.[Rule 45bis.6(d); GL/ISPE 15.91; ]

If applicants request a review of the non-unity finding they must pay a review fee. If no fee is paid, the request for review is considered not to have been made.

Similar to the protest procedure, a Review Panel is established consisting of the examiner responsible for the file, an examiner as chairperson of the Review Panel and a further examiner. This Review Panel will, in case of entry into the European phase, constitute the Examining Division (see GL/PCT‑EPO B‑VII, 7.2). The examiner dealing with the file will make a first assessment of the arguments made by the applicant and will then discuss the case with the members of the Review Panel to come to a decision.

The purpose of the Review Panel is to determine whether the lack-of-unity objection was justified on the basis of the reasoning given in the SISR. The review does not include re-evaluation to determine possible additional grounds for lack of unity.

Where the Review Panel determines that the objection was not justified, it will inform the applicant with Form 503; no reasoning needs to be given. Furthermore, it will order the reimbursement of the review fee. A corrected SISR must then be established on all claims.

If the Review Panel considers that the objection is completely or partially justified, it will communicate this to the applicant with Form 503. In these cases, reasoning must be given indicating why the objection is (at least partially) upheld. This reasoning should also address the applicant's relevant arguments. The review fee will not be reimbursed. In the case of an only partially justified lack-of-unity objection, a corrected search report taking the result of the review into account must be established.