(a) The month the Board mails the annuitant a notice saying that the Board finds that he or she is no longer disabled based on evidence showing:

(b) The month in which the annuitant demonstrated his or her ability to engage in substantial gainful activity (following completion of a trial work period);

(c) The month in which the annuitant actually does substantical gainful activity where such annuitant is not entitled to a trial work period;

(d) The month in which the annuitant returns to full-time work, with no significant medical restrictions and acknowledges that medical improvement has occurred, and the Board expected the annuitant's impairment(s) to improve;

(e) The first month in which the annuitant failed without good cause to do what the Board asked, when the rule set out in paragraph (b)(2) of § 220.179 applies;

(f) The first month in which the question of continuing disability arose and the Board could not locate the annuitant after a suitable investigation (see § 220.179(b)(3));

(g) The first month in which the annuitant failed without good cause to follow prescribed treatment, when the rule set out in paragraph (b)(4) of § 220.179 applies; or

(h) The first month the annuitant was told by his or her physician that he or she could return to work provided there is no substantial conflict between the physician's and the annuitant's statements regarding that annuitant's awareness of his or her capacity for work and the earlier date is supported by the medical evidence.

(i) The month the evidence shows that the annuitant is no longer disabled under the rules set out in §§ 220.177 through 220.180, and he or she was disabled only for a specified period of time in the past as discussed in § 220.21 or § 220.105;