They'll always be Heterocera, the moth clade, but if they evolve into a form that doesn't look like a moth they're not really moths any more.
Hence the problem with colloquial naming traditions. We arbitrarily decide what is an isn't a moth based on our feeling at the time.
Is a chihuahua a wolf? Most would say no. Did chiahuahuas evolve from a wolf-like ancestor? Most likely. We will say that chihuahuas and wolves are still dogs, but when did those wolves stop being wolves and become chihuahuas? That dividing line would also be an arbitrary one.
The system that science has settled on is cladistics, and in that system you never evolve out of your clade. This differs from the colloquial method where species are arbitrarily assigned to different groups based on shifting notions of what is or isn't indicative of a group.