Lulamoon

Trixie glared at the blue gem she was supposed to be manipulating. Princess Luna sat back calmly and watched her student as Trixie struggled to enlarge the gem. After a brief moment of success, she managed to double its size, but then, with a faint pop, the unrelenting gem shrank once again. Trixie glared at it some more. Princess Luna lifted her head slightly.

"Beatrix, you are doing well. All you need to do is focus your concentration for just a few seconds more. You almost have it." Trixie took a few deep breaths. She picked up, and slowly began to rotate the sapphire with her magic. With every rotation, it grew bigger and bigger until it was the size of Trixie's head. Straining with the effort, Trixie managed to complete the spell, and the newly enlarged gem clattered onto the table.

Princess Luna gave a nod of approval. "Excellent work, Beatrix. Now try to--" At that moment, the door banged open and Princesses Celestia and Twilight walked in. Trixie bowed to each of them in turn, then faced Princess Luna.  Princess Celestia spoke:

"Sister, Princess Twilight Sparkle and myself wanted to witness Beatrix's training. Is that all right with you and your student?" Trixie barely gave a nod. She didn't even want to look at Twilight; though she had been forgiven, Trixie still retained a lasting feeling of guilt towards the purple alicorn. Twilight Sparkle cleared her throat.

"Can we get on with it, please?" Trixie hastily backed up and prepared to work her shrinking spell. She glared at the large gem, willing it to obey her. Trixie focused her magic and, using every ounce of concentration she possessed, cast the spell. A lilac beam hit the gem, and Trixie lifted it up, again twirling it slowly, willing it to shrink every time it turned around, until it was finally normally sized. Princess Twilight gave an approving nod, and Princess Luna smiled proudly.

"Very well done, Beatrix. Now, change the color to scarlet."

Trixie took a breath and lifted up her head. She was soaked in sweat but proud of her success. She lifted up the gem and proceeded to twirl it gently. With every twirl, the color melted to dark blue, which gave way to purple, which faded to red. With a gasp, Trixie dropped the sapphire-ruby on the desk. It glowed slightly, and Twilight Sparkle examined it. Princess Luna levitated her blue quill and wrote down 'enlarge/shrink' and 'change color.' Twilight straightened up and spoke:

"Trixie, I would say that you have a basic level of magic skill, but you are very clever and you have the knack for finding intuitive ways to bend that magic into spells that would normally exceed a unicorn of your ability. I can also say that--" Twilight broke off for a second. She cleared her throat and began again: "--that you have indeed changed from the mare I once knew to a humble, modest, good pony."

Princess Celestia agreed. "We all have seen what you have done, Beatrix, but we have forgiven you, and you are using your second chance wisely. Unfortunately, many other ponies in Equestria do not feel the same way. We, along with my sister, will help you find a way to blend back into their midst."

"But...everypony already knows the name 'Trixie' and they hate me. How can I get close enough to convince them I'm not the same?" Trixie asked.

"Call yourself another," suggested Princess Luna. "Call yourself what you think is a name that fits you, yet one that other ponies do not know you by."

Trixie considered this. "Nopony knows me as just Beatrix Lulamoon; they know me as the Great and Powerful Trixie. I don't want to be known as Beatrix...I could just go as Lulamoon."

"You most certainly could," said Princess Celestia softly.

"Then," Trixie said, "I shall call myself 'Lulamoon' until ponies come to know and love me. Only then will I revert to Trixie."

Trixie Lulamoon.