Complex sentence: In 1998 Boeing proposed new longer range variants of the 777X; taking advantage of the Trent 800's growth capability, Rolls-Royce designed and built an improved engine designated Trent 8104 which was later scaled upwards to the even larger 8115.
Split into simpler sentences: In 1998 Boeing proposed new longer range variants of the 777X. Taking advantage of the Trent 800's growth capability, Rolls-Royce designed and built an improved engine designated "Trent 8104", which was later scaled upwards to the even larger 8115.