Can a witness statement be withdrawn?
You can approach prosecution and express your desire not to be a witness, but in DV cases, it is nearly always up to the prosecutor and not you. If your statement was taken under any sort of evidence act it can be tendered in court regardless of whether you show as a witness. If you recant you could be charged with hindering prosecution, providing a false statement, etc. Most places nowadays have what is normally referred to as a “victim services” division within the police or prosecution. I would strongly suggest you speak to them about your reservations and feelings regarding this matter.