Help Trevenant & dusknoir gx attack

[Guzma4GAME]

For trev noir's gx pale moon if you retreat is the effect still in place or does the new active not get knocked out?
It reads:
'At the of your opponent's turn,the defending pokemon will be knocked out. If this pokemon has at least 1 extra energy (in addition to this attack's cost),discard all energy from your opponents active pokemon

 

[Yaginku]

"Defending Pokemon" refers to the Pokemon on the receiving end of the attack. This effect is put on them, and it will disappear if they retreat or evolve.