Unlike dungeons you cannot reset them by joining a group and changing the difficulty or doing it yourself, the only consistent way I have found to do it is just leave the arena and wait 10 min if you don't have the quest, it's torture if you're trying to trifecta or push your scores...
I play DPS in magical mystical elf game, my raid leaders have determined that I play beam character
https://youtube.com/@rkindaleft
All Solo, Dungeon and Arena trifectas.
8/10 Trial trifectas.
Tick Tock Tormentor | Immortal Redeemer | Gryphon Heart | Godslayer | Dawnbringer | Planesbreaker | Dream Master | Unstoppable