This paper explores two forms of disconfirmation of candidate propositions in polar questions in Korean ordinary and airline service calls: ‘negation’ and ‘replacement’ responses. In airline service calls, questioners yield repetitional questions in third position ensuing both negation and replacement responses, fixing registration, setting precise information on record. In ordinary calls, meanwhile, questioners may provide another, reviewed question ensuing negation responses, trying to (re-)institute a common ground with respondents. It is demonstrated that the varying ways in which third-position questions are employed can be defined by the interactional nature as well as by the disconfirmation form.