User blog comment:Maki Kuronami/Weapons Guide (Basics)/@comment-4931331-20160127200900/@comment-24385282-20160221034604

It's a bit difficult to understand what you're asking, but as with Crescent Rose, you can allow one form of a weapon to be used even when that weapon is in a different form. Ruby constantly uses the sniper rifle of her weapon even while it is in scythe form.

If you mean you want your weapon to be able to use a knife in both knife- and gun-forms, that's fine. If you want it to look like a gun or like a knife in both forms, that's okay as well. Lie Ren's twin pistols cover both points - in fact, they don't even transform; they just have both forms available constantly, and their only transformation is from active to storage.