§ 1. If the defender of the bond prudently thinks that either the flaws mentioned in can. 1688 or the lack of a dispensation are not certain, the defender of the bond must appeal against the declaration of nullity to the judge of second instance; the acts must be sent to the appellate judge who must be advised in writing that a documentary process is involved. § 2. The party who considers himself or herself aggrieved retains the right of appeal.
Source: Code of Canon Law (Vatican.va)