218.42—When a parent annuity ends.
(a) Tier I.
The tier I benefit of a parent annuity ends with the earliest of the last day of the month before the month in which the parent—
(2)
Becomes entitled to an old age benefit under the Social Security Act that is equal to or larger than the tier I benefit of the parent annuity before any reduction for the family maximum, unless he or she is also entitled to a tier II benefit (reduction for the family maximum is discussed in part 228 of this chapter );
(3)
Becomes entitled to another survivor annuity in a larger amount, unless he or she elects to be paid the smaller annuity; or
(4)
Remarries after the employee's death, unless he or she marries a person who is entitled to Social Security or Railroad Retirement Act benefits as a divorced spouse, widow, widower, mother, father, parent, or disabled child.
(b) Tier II.
The tier II benefit of a parent annuity ends with the earliest of the last day of the month before the month in which the parent—
(3)
Becomes entitled to another survivor annuity in a larger amount, unless he or she elects to be paid the smaller annuity.