20 C.F.R. § 404.1592a : Employees' Benefits — SOCIAL SECURITY ADMINISTRATION — FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) — DETERMINING DISABILITY AND BLINDNESS —CONTINUING OR STOPPING DISABILITY — The reentitlement period

(a) General. The reentitlement period is an additional period after 9 months of trial work during which you may continue to test your ability to work if you have a disabling impairment, as defined in §404.1511. If you work during the reentitlement period, we may decide that your disability has ceased because your work is substantial gainful activity and stop your benefits. However, if, after the month for which we found that your disability ceased because you performed substantial gainful activity, you stop engaging in substantial gainful activity, we will start paying you benefits again; you will not have to file a new application. The following rules apply if you complete a trial work period and continue to have a disabling impairment:
(1) The first time you work after the end of your trial work period and engage in substantial gainful activity, we will find that your disability ceased. When we decide whether this work is substantial gainful activity, we will apply all of the relevant provisions of §§ 404.1571-404.1576 including, but not limited to, the provisions for averaging earnings, unsuccessful work attempts, and deducting impairment-related work expenses, as well as the special rules for evaluating the work you do after you have received disability benefits for at least 24 months. We will find that your disability ceased in the first month after the end of your trial work period in which you do substantial gainful activity, applying all the relevant provisions in §§ 404.1571-404.1576.
(2)
(i) If we determine under paragraph (a)(1) of this section that your disability ceased during the reentitlement period because you perform substantial gainful activity, you will be paid benefits for the first month after the trial work period in which you do substantial gainful activity ( i.e. , the month your disability ceased) and the two succeeding months, whether or not you do substantial gainful activity in those succeeding months. After those three months, we will stop your benefits for any month in which you do substantial gainful activity. (See §§404.316, 404.337, 404.352 and 404.401a.) If your benefits are stopped because you do substantial gainful activity, they may be started again without a new application and a new determination of disability if you stop doing substantial gainful activity in a month during the reentitlement period. In determining whether you do substantial gainful activity in a month for purposes of stopping or starting benefits during the reentitlement period, we will consider only your work in, or earnings for, that month. Once we have determined that your disability has ceased during the reentitlement period because of the performance of substantial gainful activity as explained in paragraph (a)(1) of this section, we will not apply the provisions of §§404.1574(c) and 404.1575 regarding unsuccessful work attempts, the provisions of §404.1574a regarding averaging of earnings, or the special rules in §§404.1574(b)(3) (iii) and 404.1575(e) for evaluating the work you do after you have received disability benefits for at least 24 months, to determine whether benefits should be paid for any particular month in the reentitlement period that occurs after the month your disability ceased.
(ii) If anyone else is receiving monthly benefits based on your earnings record, that individual will not be paid benefits for any month for which you cannot be paid benefits during the reentitlement period.
(3) The way we will consider your work activity after your reentitlement period ends (see paragraph (b)(2) of this section) will depend on whether you worked during the reentitlement period and if you did substantial gainful activity.
(i) If you worked during the reentitlement period and we decided that your disability ceased during the reentitlement period because of your work under paragraph (a)(1) of this section, we will find that your entitlement to disability benefits terminates in the first month in which you engaged in substantial gainful activity after the end of the reentitlement period (see §404.325 ). (See §404.321 for when entitlement to a period of disability ends.) When we make this determination, we will consider only your work in, or earnings for, that month; we will not apply the provisions of §§404.1574(c) and 404.1575 regarding unsuccessful work attempts, the provisions of §404.1574a regarding averaging of earnings, or the special rules in §§404.1574(b)(3) (iii) and 404.1575(e) for evaluating the work you do after you have received disability benefits for at least 24 months.
(ii) If we did not find that your disability ceased because of work activity during the reentitlement period, we will apply all of the relevant provisions of §§ 404.1571-404.1576 including, but not limited to, the provisions for averaging earnings, unsuccessful work attempts, and deducting impairment-related work expenses, as well as the special rules for evaluating the work you do after you have received disability benefits for at least 24 months, to determine whether your disability ceased because you performed substantial gainful activity after the reentitlement period. If we find that your disability ceased because you performed substantial gainful activity in a month after your reentitlement period ended, you will be paid benefits for the month in which your disability ceased and the two succeeding months. After those three months, your entitlement to a period of disability or to disability benefits terminates (see §§404.321 and 404.325 ).
(b) When the reentitlement period begins and ends. The reentitlement period begins with the first month following completion of 9 months of trial work but cannot begin earlier than December 1, 1980. It ends with whichever is earlier-
(1) The month before the first month in which your impairment no longer exists or is not medically disabling; or
(2)
(i) The last day of the 15th month following the end of your trial work period if you were not entitled to benefits after December 1987; or
(ii) The last day of the 36th month following the end of your trial work period if you were entitled to benefits after December 1987 or if the 15-month period described in paragraph (b)(2)(i) of this section had not ended as of January 1988. (See §§404.316, 404.337, and 404.352 for when your benefits end.)
(c) When you are not entitled to a reentitlement period. You are not entitled to a reentitlement period if:
(1) You are entitled to a period of disability, but not to disability insurance cash benefits;
(2) You are not entitled to a trial work period;
(3) Your entitlement to disability insurance benefits ended before you completed 9 months of trial work in that period of disability.

20 C.F.R. §404.1592a

49 FR 22273, 5/29/1984, as amended at 58 FR 64883, 12/10/1993; 65 FR 42787, 7/11/2000; 71 FR 66856, 11/17/2006