Arbitrary Public Announcement Logic (APAL) and its variants are proposed to formalize knowability dynamically based on public announcements as the means to update knowledge. In this paper, we introduce yet another variant HAPAL of APAL, which is based on questions instead of announcements, and captures knowability as knowing how to know by asking questions. Therefore, the prime modality in our language can also be viewed as a know-how operator sharing the same ∃□ bundled structure as logics of knowing how in the literature. This change in the semantics of the
arbitrary announcement operator results in a highly non-trivial logic, which departs from the existing versions of APAL. As we will show, it is already strictly more expressive than APAL and epistemic logic on S5 models in the single-agent case. Moreover, it lacks compactness and Craig interpolation property. We also provide a sound and weakly complete axiomatization.