Summary: Progress in understanding symmetry-protected topological (SPT) phases has been greatly aided by our ability to construct lattice models realizing these states. In contrast, a systematic approach to constructing models that realize quantum critical points between SPT phases is lacking, particularly in dimension \(d > 1\). Here, we show how the recently introduced notion of the pivot Hamiltonian – generating rotations between SPT phases – facilitates such a construction. We demonstrate this approach by constructing a spin model on the triangular lattice, which is midway between a trivial and SPT phase. The pivot Hamiltonian generates a \(U(1)\) pivot symmetry which helps to stabilize a direct SPT transition. The sign-problem free nature of the model – with an additional Ising interaction preserving the pivot symmetry – allows us to obtain the phase diagram using quantum Monte Carlo simulations. We find evidence for a direct transition between trivial and SPT phases that is consistent with a deconfined quantum critical point with emergent \(SO(5)\) symmetry. The known anomaly of the latter is made possible by the non-local nature of the \(U(1)\) pivot symmetry. Interestingly, the pivot Hamiltonian generating this symmetry is nothing other than the staggered Baxter-Wu three-spin interaction. This work illustrates the importance of \(U(1)\) pivot symmetries and proposes how to generally construct sign-problem-free lattice models of SPT transitions with such anomalous symmetry groups for other lattices and dimensions.