When Should I Stop Progyluton While Taking Letrozole For PCOS?

Hi doctor I’m have a PCOS and trying to get pregnant So l take a Progyluton for 2 months my doctor tell me to take a sonar in 12day of period l do that so write to me a letrazole to take at day 2 of next period but l forget to ask her if l stop take a Progyluton when l take a letrazole ?? Or continue taking them together??