Actually, originally when King Liang caught the person sent by Yan Kingdom to spread rumors in Yanwo, and mentioned wanting to cooperate with Yan Kingdom to meet the Ninth Prince of Yan Kingdom, Xiao Rongyan initially intended to ignore it.
However, when King Liang mentioned that Bai Qingyan was feared by other nations and would be a formidable opponent to Yan Kingdom in the future, and expressed his willingness to join hands with Yan Kingdom to eliminate Bai Qingyan, only then did Xiao Rongyan feel it was a matter worth his attention.
Later on... the disaster relief in Yanwo by King Liang led to a civil revolt. Xiao Rongyan sent his man to Dadu City to observe the situation and act accordingly. If King Liang had the means to avoid punishment by the Emperor upon being escorted back to Dadu City, Xiao Rongyan's man would meet King Liang under the identity of the Ninth Prince of Yan Kingdom, Murong Yan, to see what King Liang had planned.