Sadly the 2018 return needs to be amended to release the passive losses and if there is nothing to carry forward the loss is gone forever. If a loss of somekind is still available to be carried forward you would have to amend the 2019 then 2020 and finally 2021 return until it is used up completely. However you can no longer get a refund for a 2018 amendment ... a most unfortunate situation. This is why using a DIY program when you have something unusual that you are not familiar with is not a wise choice.
