“Dear Mr. President,” Sullivan began, “Effective April 3, 2021, having previously satisfied statutory requirements set forth in 28 U.S.C. § 371(c), I intend to retain the office of District Judge pursuant to 28 U.S.C. § 371(b)(1).” I intend to render substantial judicial service to the United States District Court for the District of Columbia pursuant to 28 U.S.C. § 371(e).”
“Dear Mr. President,” Sullivan began, “Effective April 3, 2021, having previously satisfied statutory requirements set forth in 28 U.S.C. § 371(c), I intend to retain the office of District Judge pursuant to 28 U.S.C. § 371(b)(1).” I intend to render substantial judicial service to the United States District Court for the District of Columbia pursuant to 28 U.S.C. § 371(e).”
28 U.S. Code § 371 - Retirement on salary; retirement in senior status https://www.law.cornell.edu/uscode/text/28/371
Retiring in this position and stepping down, from understanding of the statute, are not the same thing.