A ward is placed on a person or location to protect the person and/or place from negative energy, There is noway to turn the ward against the intended recipient of the casting's protection. To have the effects of a ward removed from a specificplace or personone would need to break or destroy the ward so that it would no longer protect the person or place from harm. One could do this with a hex breaker or spellbreaker casting.
Wards are meant to protect a person. They can be quite powerful and difficult to break. They are meant to keep castings out, but could also act to send negative energy at an attacker. Are you trying to break another witches ward so it sends the energy inward instead of outward? I do not think that is possible unless you somehow add something to them. Say you collect baneful herbs and bury them on top of the wards, but even then it is no guarantee. Some wards might have plans for that.
What you can do, and I am not advocating this because it will be more effort than it is worth, is break the ward with a series of little attacks. Strengthen your defenses first and chip away at the other witches with smaller hexes to weaken the ward until it breaks. However, if a witch is skilled enough to cast a decent ward, they are wise enough to know they need more than one line of defense. They could have spiritual allies, magikal traps like witches bottles, even plants and animals could be enchanted to absorb and ground any negativity cast at the witch.
I am not saying you will not get lucky and manage to harm this witch with a spell. However, I would not waste the energy on them and instead focus it on yourself. If you feel so slightest you need to curse them, or send some karmic retribution there way, I will not argue. But cast one baneful working, then focus on improving your own life.
