Transmute Weapon

You transmute a non-magical weapon into a different weapon of the same category (simple melee, martial ranged, etc.), and size. Its cost remains unchanged.

You can also expand a spell slot to transmute a magic weapon into a different magic weapon of the same category and size. The spell slot expanded is equal to the enchantement level (+1/+2/+3) multiplied by two. Any magical ability other than +1/+2/3 is not carried to the new form the weapon has been transmuted into except if the new form has compatible features and if your DM allows it.