on second thought
US /ɑːn ˈsek.ənd θɑːt/
UK /ɑːn ˈsek.ənd θɑːt/

1.
pensando bem, depois de pensar melhor
used to say that you have changed your mind or that you have a new idea that is better than your previous one
:
•
I'll have the chicken, no, on second thought, I'll have the fish.
Vou querer o frango, não, pensando bem, vou querer o peixe.
•
Let's go to the park. Actually, on second thought, it might rain.
Vamos ao parque. Na verdade, pensando bem, pode chover.