Often, if someone has been around awhile, especially retiring, there is an understood agreement that they have appointments or other issues requiring the use of sick days. Basically, managers stop really scheduling you and you use the MAP, PB and FH for your last days. Your local management may vary and I wouldn't do this for someone that is new, to me <5 years, unless it was known and understood they were pursuing education and would be moving into their career field upon graduation.