To be clear, the bill doesn’t eliminate the Medicaid expansion coverage for those who are enrolled prior to 2020 in the current expansion states. But if those enrollees have a break in coverage for more than one month after Dec. 31, 2019, they won’t be able to re-enroll (unless a state wanted to cover the additional cost itself).
The Republican plan includes another notable change to Medicaid. It would cap the amount of federal funding that states can receive per Medicaid enrollee, with varying amounts for each category of enrollee, such as children, and the blind and disabled. Currently, the federal government guarantees matching funds to states for qualifying Medicaid expenses, regardless of cost. Under the GOP bill, states have the option of receiving a block grant, rather than the per-capita amounts, for traditional adult enrollees and children – not the elderly or disabled. States also have the option of instituting work requirements for able-bodied adults, but not pregnant women.
http://www.factcheck.org/2017/03/the-facts-on-the-gop-health-care-bill/