Open the config with /bar.
Click Bar 1 (Or whichever bar you want to change) on the left side menu.
Click State Configuration on the top menu.
Here you can set what bar to show when your in what form, Prowling included.
Alternatively, you could make macros for your buttons that does paging for you
Ex:
#showtooltip
/cast [stealth] Pounce; [stance:1] Growl; [stance:3] Savage Roar(Cat Form); Hibernate
This allows whatever it macro is bound to to use pounce from stealth, growl from bear form, savage roar from cat form, or hibernate from an other form.