Here's the history of L.E.G.I.O.N., post-boot with what happened to Phase, from the Legion Helpfile:
L. E. G. I. O. N.
The group known as the Liscensed Extra-Governmental Interstellar Operatives Network (L. E. G. I. O. N. for short) was founded by Vril Dox II, an ancestor of Brainiac 5 and five others, including a Durlan, the female Dryad, Strata, the Talokian heroine Lyrissa Mallor when they broke free of the Dominion-run Starlag in which they were held hostage to their planets' non-interference with their late twentieth-century invasion of Earth (Invasion! # 1-2). Dox maneuvered them into liberating his homeworld Colu from the Computer Tyrants that ran it, and then, with the hired help of the bounty hunter Lobo, they overthrew the drug lords who ran Cairn, home planet of fellow Starlag inmate Garryn Bek (L. E. G. I. O. N. '89 # 1-6). Due to Dox's machinations, they stayed together, and L. E. G. I. O. N. became known as a force for justice throughout the galaxy. Shortly after the group was founded, the Durlan disappeared, and was replaced by a mysterious woman who had lost her memory and became known as Phase (L. E. G. I. O. N. '89 # 9). The group also included, in later times, another Talokian heroine, Lyrissa Mallor's daughter Lydea (L. E. G. I. O. N. '91 # 27) and Lar Gand before he began his super-hero career as Valor (L. E. G. I. O. N. '90 # 16-19, Annual # 1).
While Valor did not stay with the group for long, he maintained somewhat cordial relations with them. Not long after he began his Valor career, he came to Dox for some anti-lead serum and repairs to his ship, and in the days that it took he returned the favor by participating in a mission with Dox, Stealth, Phase and Captain Comet to the planet Poriaxus, where Dox invested his money with the leaders of a culture in which they would be put to death if the money were to be lost (Valor # 4, Legion of Super-Heroes (3rd series) # 119).
Control of the group was later usurped by Lyrl Dox, son of Vril and Stealth and also an ancestor of Brainiac 5, but Vril managed to stop him from taking mental control of the galaxy,and the group's reins were handed over to the much more altruistic Captain Comet, who summoned Vril back into action when the Legion of Super-Heroes accidentally freed Brainiac (Showcase '96 # 11), who Vril, despite the protests of Stealth (who then had to babysit Lyrl), managed to defeat with the help of L. E. G. I. O. N. Officer Taptree and the Legion of Super-Heroes (Showcase '96 # 12). During that incident, Phase and Strata noticed the disappearance of Phase's touchstone, which she had once left on Earth and which found its way into the possession of the villainous Poltergeist (Legion of Super-Heroes (3rd series) # 87), something Phase realized after she and Captain Comet engineered a futile search of Cairn to find it. Once she realized this, Phase took off for Earth to search for it there (Legion of Super-Heroes (3rd series) # 94), escorted by Officer Taptree (Legion of Super-Heroes (3rd series) # 96). When Phase and Taptree got to Earth, they tried to steal the touchstone from its then-current user, Tiffany Cross, but Phase ended up disappearing into it instead (Legion of Super-Heroes (3rd series) # 97). Alarmed by this, Tiffany and Taptree called the honeymooning Ultra Boy and Apparition to tell them of the situation, whereupon Phase's and Apparition's touchstones merged, and Apparition disappeared into the touchstone as well. Inside the Touchstone, Apparition and Phase met one another and have discovered that there is some link between them, and that Phase and Apparition are, in some way, two parts of a larger whole. Phase and Apparition, merged into one being, emerged from the touchstone during the Legion's fight against C. O. M. P. U. T. O., and the individual has returned to the thirtieth century with the Legion, leaving Taptree to return to the force alone (Legion of Super-Heroes (3rd series) # 98-100). Phase and Apparition later discovered that they are two of three parts of the same person, their father having been a Carggite who could split into three people (Legion of Super-Heroes (3rd series) # 100, 102).