One of five protesters arrested at the September World Bank summit was acquitted yesterday of disorderly conduct. Moments after the acquittal, the prosecution sought to amend similar charges against two other defendants. Tam Wai-pang, 25, was freed by Eastern magistrate Richard Donald after Lawrence Lok SC said his client had no case to answer. The student had denied a charge of disorderly conduct after allegedly breaking through a police cordon in O'Brien Road, Wan Chai, on September 21. The arresting officer said it was chaotic at the time of the arrest and agreed to withdraw his evidence after a video of the incident failed to show Mr Tam's conduct was disorderly. Two other protesters jointly charged with Mr Tam - Tam Chun-yin, 25, and Wong Shui-ying, 39 - also deny disorderly conduct. Wong Shui-hung, 21, and Chan Siu-ping, 24, deny four charges of assaulting police officers. Moments after Mr Tam's acquittal, prosecutor Derek Pang sought to substitute two charges of obstructing police officers for the disorderly conduct charges. Mr Donald has turned down a previous prosecution request to amend the charges. He will rule on the latest application when the trial resumes on May 11.