Electoral control is a scenario where an election chair changes the structure of an election by actions such as adding or deleting either candidates or voters with the goal of either making a favorite candidate win or precluding a despised candidate’s victory. Much work has been done on the computational complexity of controlling elections for single-winner voting rules, yet much less work on the control complexity for multiwinner voting rules which aim at electing not only a single winner but a winning committee of candidates. Meir et al. [20] initiated the investigation of electoral control for multiwinner voting rules, including single nontransferable vote (SNTV) and bloc voting. We study these two rules with respect to control by adding, deleting, or replacing candidates.