Nick,
Very simple!....Be very careful and gentle!....I start digging up, removing some of the transplanting medium (coarse sand and lots of perlite mix) around the corm/pup until I start seeing new roots!....You don’t need to pull out and remove the whole plant!...Once you see any new roots formed just cover her up again!....Also, if you don’t see any new roots formed yet, be patient!....Give the Nana plant more time!....Eventually she will be rooting!....
Usually I inspect the Nana corm/pup/plant for rooting (new roots formed) after 10 days from being transplanted!.....If I don’t see any new roots, then I will inspect her between 8 to 10 days again!....
