How do your repeal social security?
Step 1: A Representative in Congress draws up a Bill to repeal Social Security.
Step 2: The House of Representatives passes said Bill.
Step 3: The Senate passes said Bill.
Step 4: The President of the United States signs the bill into law.
Next question?
That will happen when it goes bankrupt. 25 years from now or less SS will not exist...at least not in its present form. Whatever replaces it will be a self-sustaining, investment based, actuarially sound system because, in the end, the truth does dictate what has to done.