There's a way to withdraw OA dollars (dollars above $20,000) ahead of SA dollars if you're age 55+ and have a decently funded (or better) RA:
1. Open a CPF Investment Account if you don't already have one.
2. Buy some investment using OA dollars. A 6 month T-bill, for example.
3. Close your CPF Investment Account, and transfer the investment(s) to your CDP account in the process.
4. Sell the investment, or (as with a T-bill) let it mature.
All of this is moot starting in early 2025 when Special Accounts will be closed for all CPF members age 55+.
Or you could transfer your OA dollars to a qualified elder family member's (such as a grandparent's) Retirement Account. The additional dollars will boost the elder's monthly retirement income. The elder could hand you back that incremental income every month (if the elder volunteers to do so). Also, if you are that elder's CPF nominee, any residual balances will be paid to you when the elder passes on. To be clear, all OA dollars transferred to this elder belong to the elder, and the elder could change his/her mind.