In 664, Liu Rengui, by now carrying the higher rank of commandant, submitted a petition pointing out that the soldiers stationed at Baekje was facing much difficulties, after having been away from home for five years, and should be greatly rewarded. Emperor Gaozong partially agreed with Liu Rengui's pleas and sent Liu Renyuan to relieve him with new reinforcements, but Liu Rengui did not believe this to be the right course of action further, believing that the army should remain to prepare for the next campaign against Goguryeo, and Emperor Gaozong permitted Liu Rengui to remain at Baekje. However, the following year (665), as Emperor Gaozong was preparing for a grand ceremony to make sacrifices to Heaven and Earth at Mount Tai, Liu Rengui returned to Tang along with emissaries from Silla, Tamna, Japan, and the former Baekje, to attend to Emperor Gaozong during the ceremony. Emperor Gaozong was pleased by these emissaries' presence, and promoted Liu Rengui to the post of imperial censor, keeping him in the imperial administration. He also gave Liu Rengui the designation Zhi Zhengshi (), making him a de facto chancellor.