(1) Section 324 (amended by section 18 of the Social Welfare and Pensions Act 2008) of the Principal Act is amended -

(a) by substituting the following subsection for subsection (1):

"(1) A designated person may at any time -

(a) revise a determination of a designated person in relation to entitlement to supplementary welfare allowance -

(i) where it appears to him or her that the determination was erroneous -

(I) in the light of new evidence or new facts which have been brought to his or her notice since the date on which the determination was made, or

(II) by reason of some mistake having been made in relation to the law or the facts,

or

(ii) where -

(I) the effect of the determination was to entitle a person to supplementary welfare allowance, and

(II) it appears to the designated person that there has been any relevant change of circumstances since that determination was made,

or

(b) revise the decision of an appeals officer where -