However, if a general power created on or before October 21, 1942, is partially released on or after the later of those dates, a subsequent exercise of the power will constitute an exercise of a general power of appointment. The legal disability referred to in this paragraph is determined under local law and may include the disability of an insane person, a minor, or an unborn child. The fact that the type of general power of appointment possessed by the holder actually was not generally releasable under the local law does not place the holder under a legal disability within the meaning of this paragraph. In general, however, it is assumed that all general powers of appointment are releasable, unless the local law on the subject is to the contrary, and it is presumed that the method employed to release the power is effective, unless it is not in accordance with the local law relating specifically to releases or, in the absence of such local law, is not in accordance with the local law relating to similar transactions.
26 C.F.R. § 25.2514-2