Item specific changes

[calicocatcollectable]

I used the feature:  Have one to sell?  Sell now.  I am unable to change one "Item Specifics" category called "Modification Description"  It just doesn't show up when I try to revise my listing but it is in the listing.  I've tried yes, no, and nothing under Modified Item, but that doesn't allow me to change the description.  Do I have to start over on my listing?