Things appeared to change in 693, however, after Li Chengqi's mother Crown Princess Liu and Li Dan's concubine Consort Dou were killed by Wu Zetian based on false accusations by the lady in waiting Wei Tuan'er (韋團兒).
Wu Zetian was overthrown in 705 in a coup led by the officials Zhang Jianzhi, Cui Xuanwei, Jing Hui, Huan Yanfan, and Yuan Shuji.
The former Emperor Zhongzong, whom Wu Zetian had recalled from exile in 698 and to whom Li Dan had subsequently yielded the position of heir apparent, was restored to the throne.
Emperor Zhongzong died suddenly in 710—a death that traditional historians believed to be a murder carried out by his powerful wife Empress Wei and daughter Li Guo'er the Princess Anle.
Emperor Ruizong was immediately faced with the issue of whom to make crown prince—as Li Chengqi, as the oldest son overall and the oldest son of his wife, was the appropriate heir under Confucian principles of succession, but Li Longji had been the one whose accomplishments had allowed him to retake the throne.
Princess Taiping, who had already been powerful both in governance matters and in court conspiracies during Emperor Zhongzong's reign, and especially she became close to absolute power after Emperor Ruizong's return to the throne, had initially acquiesced to Li Longji's ascension as crown prince, believing that given his youth (25 at that time) he would be easy to control.
In 711, under the suggestion of the chancellors Song Jing and Yao Yuanzhi, who supported Li Longji and wanted to eliminate doubt in people's minds about who would succeed Emperor Ruizong, Emperor Ruizong made Li Chengqi the prefect of Tong Prefecture (同州, roughly modern Weinan, Shaanxi) and Li Shouli the prefect of Bin Prefecture (豳州, roughly modern Xianyang, Shaanxi), while sending Princess Taiping and her husband Wu Youji the Duke of Chu to Pu Prefecture (蒲州, roughly modern Yuncheng, Shanxi).
However, after Princess Taiping found out and objected, the plan was cancelled, and Song and Yao were demoted out of the capital Chang'an.
Meanwhile, Princess Taiping continued to highly influential in governmental matters through Emperor Ruizong, and most chancellors, commanders of the imperial guards, officials and generals were her associates.
Therefore, the survival of her power was an obvious dangerous threat and an undeniable challenge to Emperor Xuanzong's authority.
In 714, Emperor Xuanzong agreed and sent the three princes out of the capital, and Li Chengqi became the prefect of Qi Prefecture (岐州, roughly modern Baoji, Shaanxi).
Around that time, there was an incident in which Emperor Xuanzong, while on a skyway overseeing the palace, saw a guard who did not finish his meal but instead dumped some of the food in a hole.
However, Li Xian, who was present, calmly stated to Emperor Xuanzong: Your Imperial Majesty had discovered this person's fault from a skyway.
Later that day, at a feast, Emperor Xuanzong, in gladness, took off his belt, made of red jade, and awarded it to Li Xian, along with his own horse.
In 721, Li Xian became the minister of rites, a post that he served in until 726, when he again took on the honorific title Kaifu Yitong Sansi.