§1. An election must be communicated immediately to the person elected who must inform the one presiding over the college or group whether or not he or she accepts the election within eight useful days after receiving the notification; otherwise, the election has no effect.
§2. If the one elected has not accepted, the person loses every right deriving from the election and does not regain any right by subsequent acceptance but can be elected again. A college or group, however, must proceed to a new election within a month from notifcation of non-acceptance.
Source: Code of Canon Law (Vatican.va)