Han Xin
In 203 BC, after his victory at the Battle of Wei River, Han Xin conquered the Qi kingdom and sent a messenger to Liu Bang, requesting that Liu appoint him as the acting King of Qi. Liu was still trapped at Xingyang then and he was furious after hearing the request because he was expecting Han Xin to come to his aid. Zhang Liang reminded Liu Bang that if he refused to approve Han Xin's request, Han might be discontented and declare independence from Liu, putting them in a dangerous situation. Liu Bang reluctantly agreed and sent Zhang Liang to pass the king's seal to Han Xin. Zhang Liang met Han Xin and succeeded in reaffirming Han's loyalty to Liu Bang.