Enforcement of decisions. In exercising the above-mentioned powers, such Board may, in conformity with the provisions of this chapter, reverse or affirm, wholly or partly, or may modify the order, requirement, decision or determination appealed from and may make such order, requirement, decision or determination as ought to be made, and to that end shall have all the powers of the officer from whom the appeal is taken, and may issue or direct the issuance of a permit, provided that no such action shall have the effect of permitting in any district a use prohibited in that district; of rezoning; or granting a conditional use or special exception where such grant is not specifically assigned to the Board for determination under this chapter; or of permitting, without the approval of the Plan Commission, any building within the base setback area as hereinafter established by the provisions of this chapter.