It was heartbreaking to watch Celestia pass, so I know how it felt when I did the same. Twilight and Cadence burst into the room. Cadence approached me. "Luna! please, I don't want to lose you!" After Celstia had died, the three of us started hanging out more, and we became very close. "Luna!"
"Calm yourself. While we may not like it, this day is inevitable. Please, do not linger on my death. I want you to be happy."
"Luna." She placed a kiss on my forehead, and back up. Twilight immediately came forward and placed my hoof in hers. We sat there in silence for a moment before I spoke, "I want to thank you Twilight. You and your friends helped save me from nightmare moon and helped me make friends in the world." She remained silent. "I wouldn't have been able to do that without your help. had you not saved me, the world would have been shrouded in darkness forever."
"That's what friends are for." she kissed me on the forehead before backing up. Cadence and her placed their hooves over each other's shoulders as I began to dissipate. I burst into small sparkles, and went to join my sister in nothingness.