Quantum Hall antidots provide a promising geometry for probing quasiparticle transport and interference in the quantum Hall regime. Unlike conventional Fabry-Pérot interferometers, whose confined geometry may lead to Coulomb-dominated behavior, antidots offer access to both controlled quasiparticle localization and anyonic interference. In this letter, we investigate a gate-defined bilayer graphene antidot and demonstrate a tunable crossover between distinct transport regimes. By varying the antidot potential, we control the coupling between extended quantum Hall edge states and states localized around the antidot. For filling factor ν = 2 and 4 this evolution is accompanied by a doubling of the conductance oscillation period, and an evolution of the magnetic field period from φ₀/ν to φ₀ which we identify with a crossover from a Coulomb-dominated regime to an Aharonov-Bohm regime in which transport is governed by interference around the antidot. The observed crossover reveals the importance of coupling between the antidot and extended edge states and establishes gate-defined antidots as a controllable platform for quantum Hall interferometry.