The House of Lords has no power actually over the House of Commons (Parliament). But, they have a braking power, a right to scrutinise (often in very fine detail) any act of Parliament the Government (the political party currently in power) wishes to bring into law. A member's Bill may pass back and forth from the Commons to the Lords and amended several times, until it is finally approved or defeated in the House of Commons, and passed (or not) into law.