First, any individual who has claimed Social Security retirement benefits can withdraw their application within 12 months of doing so. This allows the individual’s monthly benefit to continue to grow, but they (and any family members receiving benefits based on the worker’s earnings record!) must pay back any benefits already received. This strategy could be useful for individuals who decide to go back to work within a year of claiming their benefits.
Second, going in the opposite direction (for those who wish they had claimed earlier) is to elect to receive a lump sum payout of six months of retroactive benefits, which is available to (only) those individuals who have reached their Full Retirement Age (FRA). Thus, a retiree in need of a short-term cash infusion could retroactively start their benefits if they wish they had started earlier (and take the lump sum for what they missed!).
The third strategy for recipients who have reached their FRA is to suspend retirement benefits in order to get delayed retirement credits until age 70, at the latest. This option is potentially useful for married couples because, if the higher-earning spouse had originally started benefits early (reducing their payments), subsequently suspending their benefits can increase their benefits again, such that if the higher-earning spouse dies first, the survivor will get the larger benefit amount.
Notably, those who claim a retroactive 6-month payment for delaying can do so and then also suspend their benefit after taking the lump sum, receiving the lump sum (for a small infusion of cash) and still earning delayed credits up to age 70!