When she left the show they simply crossed out her name in the scripts and had a 'yeoman of the week'
By production order Rand's last episode was #13 "Conscience..."
#14 was Galileo--featuring a one-shot yeoman
#17 was Shore Leave--featuring a one shot yeoman
#18 was Squire --------featuring a one-shot yeoman
#22 was A Taste of----featuring a one shot yeoman
I've also heard that 'Dagger' was originally written for Rand, coming along as just a yeoman rather than 'specialist in criminology' but they were already having 2nd thoughts about the ongoing relationship. The episode refers to the previous 'Christmas party'--which seems like it would be more of a Rand type reference.
Yep. Whitney herself calls "Dagger of the Mind" and "The Galileo Seven" her "least favourite episodes".
Early script treatments for episodes such as "The Trouble with Tribbles" and "City on the Edge of Forever" presumed that Rand would still be with the show.