In a Notice published August 1, 2011, the USPTO announced a policy change to comply with the recent Federal Circuit decision in In re Tanaka:

Effective immediately, the following policy is implemented. Where the only change to a patent made in an application for its reissue is the addition of a claim or claims that is/are narrower in scope than the existing patent claims, without any narrowing of the existing patent claims, the application claims are not to be rejected as failing to state an error under 35 U.S.C. §251. In addition, any rejection of record in a pending application on this basis will be withdrawn, and any new Office action issued will inform applicant of the withdrawal, and the resulting status of the application in view of the withdrawal.

The Notice states that MPEP § 1402 will be revised to reflect Tanaka.

As I discussed previously, filing a reissue application to add dependent claims may provide a useful mechanism for strengthening granted patents in view of the evolving interpretations of the patent eligibility (§101), and written description and enablement (§112) requirements.