I once agreed to my husband taking another wife when I was emotional. Can I withdraw that consent before the hearing?

You can state your current position to the court; what matters is your honest view now. A wife's consent is not a mandatory condition for approval, but the court hears her view when assessing the application. If your position has changed, say so plainly and explain why, for example ‘At the time I did not understand its effect on the children.’ Discuss this change with your husband early so that he is not surprised in front of the judge. If you signed a consent letter, bring a copy and ask a syarie lawyer the best way to explain it. It is the judge who will weigh both statements. See the first wife's consent.