You can stop the auto withdrawal of CPF OA and CPF SA at Age 55, in the client's profile page using the advanced setting. You can set the option "Auto withdraw amount above CPF Retirement sum at age 55" to "No" so that the lump sum would not be paid out. The CPF OA and CPF SA will be kept in the CPF and can be withdrawn using a Scenario at a later age.
However, do note that the CPF RA will still be created.