No. Social Security coverage is mandatory. But consider this: unlike your private plan, Social Security provides disability and survivors coverage in addition to retirement benefits. And Social Security generally offers greater protection for family members than private pensions.
A "put bond" is a bond that gives the holder the right to require the issuer of the bond to redeem the bond prior to its stated maturity date. The timing and price for the put right are set forth in the bond documents when first issued. Since the holder has the option to force the issuer to purchase back the bond before its stated maturity date, the interest rate on the bond will typically be lower than a non-putable bond.