Pretty easy.
A freeboard success story from FEMA:
Gail Cunningham Coen of Westport wishes that people would realize how easy it is to elevate your flood-prone house, especially when the Long Island Sound is just feet from your front door. “We didn’t even take the pictures off the wall,” Coen said, referring to the elevation of her home in 1994. “It took 3 days to jack it up, 3 days to build the foundation, and 3 days to lower it back down.”
After flooding destroyed her first floor in 1992, she decided she’d had enough of Mother Nature’s fury. Coen registered with the town for a grant through FEMA’s Hazard Mitigation Grant Program (HMGP) to help pay half the cost of elevating her home.
The rest of the article is here. You can read up about freeboard here.