From the code perspective you could replace all ...2d layers with their ...3d equivalents first.
If you want to reuse the ...2d parameters, you would have to come up with a way to copy these parameters into the ...3d modules and expand/repeat them.
I don’t have any information unfortunately, which approach would work best, as I assume it’s use case dependent.
However, if you want to train the new model from scratch, replacing the layers might work without any further changes.