D.C. Mun. Regs. tit. 9, r. 9-207
If a will is contested and the contest is compromised by an agreement under which the will is permitted to take effect, the tax is nevertheless imposed as though distribution had been made in accordance with the provisions of the will. In other words, where the will is permitted to stand, the tax is paid as if the compromise had not been made.
If a will is contested and the contest is settled by an agreement under which the will is withdrawn and the law of distribution and descent is allowed to operate, the tax is imposed upon those who take under the law of distribution and descent and not on those to whom a compromise payment is made for permitting the withdrawal of the will.
If a will is construed by the court, the tax shall be imposed upon those persons who are entitled to take by decision of the court and upon the shares which they are entitled to receive by reason of the court decision.
If a person renounces the share to which he or she is entitled under a will, and if the renunciation is properly filed with the court, and if the person renouncing receives no valuable consideration for the renunciation, the tax shall be imposed upon the person or persons in favor of whom he or she has renounced.
D.C. Mun. Regs. tit. 9, r. 9-207