Way to switch standard Steam login to old PoE account ?

[Razthar]

Hi,
I recently picked PoE up again, but at the time I didn't recall my old login so i just made a new one quickly to get into the game.
But i've now found my old login info and want to play on my original account.

Is there a way to change the temporary steam account i made out with my old one?

I know that it was possible if i had remembered my old account info the first time i opened the game and it asked if i wanted to link my old account. But I can't seem to find a way to get that option again. (short of deleting and completely reinstalling maybe..)