Macro that switches spells depending on if I have a particular buff up

Guides UI and Macro
1

I’m looking to make a macro that will cast sweeping strikes unless I already have the sweeping strikes buff up, in which case it will cast skullsplitter

I’ve been trying to base it on this macro that I use that casts Defensive Stance unless I already have the defensive stance buff up, in which case it will cast Battle stance

/cast [stance:2]!Defensive Stance;[known:386164]!Battle Stance;[known:386196]!Berserker Stance

2

Not possible.