Yes, I thought you were talking about removing reactions ( likes, shakas )... which I haven't seen working while testing almost every client.

But if you talk about post deletion, here is what it says:

"You cannot delete on protocol level, you can just tag a note as deleted. How relays and clients deal with this information is their choice. Eg. clients can choose to not show deleted-tagged notes; relays can actually delete it. However you can never be sure all relays to which your note got propagated do this. Pretty impossible to actually delete your note through the whole network".