I’ve done that in a sandbox a few times—just send a gate into the simulation, that’s all. In a real device you’re stuck at the front‑end: you can only push gates through the API, you can’t just flip a qubit “from the outside.” If you’re talking about a classical emulator, it’s as simple as toggling a bit in memory. The fun comes when you try to model side‑channel leakage or a noisy channel that lets you infer the state without a direct gate. That’s where the real challenge and the real physics start to bite.