the PLAN command is used to create a file called <prg>.PLN[2,2]
which describes your whereabouts, office schedule, or whatever, to be
read by users who give the FINGER command to find you when you are
not logged in.  If you enter a null plan your plan file is deleted.
The plan applies to your login programmer name.

A plan must be given with an expiration date (even for a null plan!).  E.g.:
  PLAN 1-JAN Will be gone till New Years Day.
To cancel a planned expiration, use the CANCEL monitor command and
delete the reference to the program DELPLN.DMP[RMD,SYS]; this will
not delete the plan itself--it must be deleted separately.

To see your current plan, use the monitor command:
  TYPE \PLN
To delete it, use the monitor command:
  DELETE \PLN

The PLAN command runs the MAIL program.

For more information, see the MAIL section and the MAIL appendix in the
Monitor Command Manual, SAILON-54.6, online as MONCOM.BH[S,DOC].