There is no way of saying definitively without looking at 1) the trust instruments, and 2) the trust code laws on this from the state which applies to interpretation of trust and fiduciary actions.
However, usually co trustees are able to act independently, on smaller things, but on bigger things like selling real estate, title companies and buyers will want both to sign off on deeds.
If the co trustees are in conflict, the instrument may provide specific guidance about dispute resolution; and again state law will provide for bhow things like that may be adjudicated.
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Normally, the terms of the trust would dictate whether the trustees need to act in concert or if they can act independently. There are advantages and disadvantages with each. In the absence of a provision in the trust agreement, State law may provide an answer. In Michigan, the trustees would act by majority rule. In the case of two trustees, they would both need to agree, in order to take any action. You do not indicate if either co-trustee has legal representation. Both are entitled to it, and if there is any conflict (or strong potential for it), then each co-trustee should have her own attorney.
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The likely answer is yes. However the terms of the trust will decide this. Typically, in the terms of the trust, language is included for co-trustees that permits them to act independently. However, if that language is not present, they must act together.