In general, what are you allowed to withdraw from RA after 55:
If you meet FRS at 55, you are allowed to withdraw at PEA (65) 20% of your RA (your FRS with interest), nothing more.
If you decide to pledge property to withdraw down to BRS, you can only withdraw 50% of your FRS at 55 excluding any topup monies if your FRS is formed using topup monies (ie not entirely from SA/OA).
All other means of withdrawal from RA are exceptions, like giving up your citizenship, terminal illness, etc as defined in CPFB website.
Monies in RA are reserved for your retirement, to fund your CPF Life if you opt to start payout from age 65 onwards and to be streamed out as payout from CPF Life! Any RA topups after CPF Life starts will automatically be swept into CPF LIfe as premium.