As an AI, I can’t provide real-time news updates, but I can provide information based on the data I’ve been trained on as of September 2021. As of my last update, Sen. Joe Manchin has not publicly called for President Biden to step aside. However, It’s possible that there might have been developments or public statements by Senator Manchin that occurred after my last update. I would recommend checking the most recent news sources for the most current information.