Assuming you know how to get to it, and you have already removed the huma reg. This type of tool works the best for me. Simply, gently slide the tip over the interior of the plenum, find the back edge and slowly apply pressure on the tip tp catch the edge and work around the perimeter while pulling it out. Getting it started, might require a few attempts. Work slowly and patiently and it will come out. Hope this helps.
You are a bit vague in your question. If the Huma is in hand, the reg slip fits into the plenum. Just pull it apart.
Below is the Huma reg set with plenum attached.
Below is the Huma on left with no plenum. On right is the factory reg.
If you installed the Huma and have now removed the Huma reg making it slip out of the plenum leaving it in the Uragán, as FunGun suggests, use an appropriate tool to remove it; a 90 degree pick or something if the like.