Agree with what's been said, we need much more info. But in the end tack is just tack.
All western horses should be trained to both direct rein (two hands) and neck rein (one hand). When starting a young western horse under saddle, the animal spends some time in a snaffle bit doing direct reining. Then, once the horse has a good understanding of steering the rider adds leg, seat, and neck rein cues to begin their neck reining training. Once their neck rein is good in a snaffle, they are graduated to a curb where they neck rein ONLY. But this doesn't mean that they have forgotten how to direct rein - the training is still there.
If your horse's background is western only, and you currently neck rein, then your horse should also understand how to direct rein.
Either way your horse can direct rein. If your horse can direct rein then you can go English with zero problems. I've never had a problem going back to direct reining, even on a horse who had only been neck reining for years. Direct reining is very straightforward so the horse will pick it back up very easily.