Switching to reflux milk

[NameOfUser]

My health visitor just did dd's four month check at home, she's advised to put her on a reflux or stay down milk. Been to the shops and bought cow and gate reflux formula (she has been on normal cow and gate since birth).
I still have about a quarter of a tub of it left so should I switch her straight away or keep using it til it runs out?
She's in no pain at all, hardly ever cries, has put on weight very nicely since birth but the health visitor noticed how much she brings up, probably due to a floppy larynx, and said this would probably help her keep more down.