Redemption and roll-over of debt securities require special resolution, notice with credit rating, and specified conditions. Regulation 18 requires redemption per the offer document and permits roll-over only after a special resolution of holders with fifteen days' notice disclosing credit rating and rationale; the notice must be filed with stock exchanges. Conditions for roll-over include postal ballot approval with at least 75% consent by value, a credit rating within six months disclosed in the notice, execution or continuation of a trust deed, and adequate security; non-consenting holders must be redeemed.