From what I've done through the years to take the loss you just need to tell them to liquidate and close out the desired equity so it reflects in this years tax season, this can be done right up until the last trading day of the year
Personally I'm not doing that but everyone has their own path so if that's what you want to do it's quite easy.
Worthless securities include securities that you abandon. To abandon a security, you must permanently surrender and relinquish all rights in the security and receive no consideration in exchange for it. Give them to your Broker. They throw them in their basket of goodies. Report worthless securities on Part I or Part II of Form 8949.