In Powell's speech to the UN in 2003 there was only one small reference in his conclusion related to Saddam regime change. The rest of the entire speech focused on Hiding Equipment, Thwarting Inspections, Biological Weapons, Chemical Weapons, Nuclear Weapons, Prohibited arms systems and Ties to AQ.
Quoted below is the only part I can find that has anything in common with the need for "regime change". For those who can be bothered to read the whole transcript it is clear the marketing of the invasion had all to do with convincing folks Saddam had WMD, an active nuclear weapons program and was a major supporter of global terrorism.
"And I thank you for your patience. But there is one more subject that I would like to touch on briefly. And it should be a subject of deep and continuing concern to this council, Saddam Hussein's violations of human rights.
Underlying all that I have said, underlying all the facts and the patterns of behavior that I have identified as Saddam Hussein's contempt for the will of this council, his contempt for the truth and most damning of all, his utter contempt for human life. Saddam Hussein's use of mustard and nerve gas against the Kurds in 1988 was one of the 20th century's most horrible atrocities; 5,000 men, women and children died.
His campaign against the Kurds from 1987 to '89 included mass summary executions, disappearances, arbitrary jailing, ethnic cleansing and the destruction of some 2,000 villages. He has also conducted ethnic cleansing against the Shiite Iraqis and the Marsh Arabs whose culture has flourished for more than a millennium. Saddam Hussein's police state ruthlessly eliminates anyone who dares to dissent. Iraq has more forced disappearance cases than any other country, tens of thousands of people reported missing in the past decade.
Nothing points more clearly to Saddam Hussein's dangerous intentions and the threat he poses to all of us than his calculated cruelty to his own citizens and to his neighbors. Clearly, Saddam Hussein and his regime will stop at nothing until something stops him."
CNN.com - Transcript of Powell's U.N. presentation - Feb. 6, 2003