I guess you are using SBT. What version??? Check out g_setprn.prg. Generally they just use "set printer to". However, they (SBT) asks the user to select a printer via a dialog. They use getprinter to supply the default printer and then allow the user to pick a new printer. Then print the job using "PRINTJOB"
where they set orientation with an if statement.
if something
"REPLACE expr WITH STRTRAN(expr, "ORIENTATION=0", "ORIENTATION=1")"
else
REPLACE expr WITH STRTRAN(expr, "ORIENTATION=1", "ORIENTATION=0")
endif


I don't know what more I can say.

P.S. I recall at one time there was a problem using VFP 5.0 where it was required to reset the printer between jobs. But this does not sound like your problem.