You can use:
Zombie=(AZombieEnemyCPP*)UGameplayStatics::GetActorOfClass(AZombieEnemyCPP::StaticClass());
if there’s only one in the level, or you can do:
TArray<AActor*> zombieList;
UGameplayStatics::GetAllActorsOfClass(AZombieEnemyCPP::StaticClass(),zombieList);
if there are more than one, but then you’ll need to find which one it is that you’re wanting to move to the ceiling - maybe with a proximity test.