At this excellent compilation of Kerry and Bush's service records, one can read that officially, John Kerry was supposed to be drilling 48 times per year in the Ready Reserve, and they thought he was.
The first document is offering him the opportunity to continue in Ready Reserve status, rather than transfer to Standby Reserve. Apparently he declines to get his hair cut, because the second page places him in Standby effective July 1, 1972.
While you're at the site, be sure to read the demolition of the Boston Globe's claim that George W. Bush was supposed to be drilling with an ANG unit in Massachusetts in September '73. His pro forma request (when the war ended, "early outs" for education were routine) for discharge is here.
True sadists will enjoy the picture drawn of the service of the President in 1972 and 1973. Count em: 36 days of attendance in '72 and 46 in '73. Note the heavy duty in July '73 so he wouldn't have to drill when he was headed to Massachusetts.