1. An administrative decision-maker is not functus officio and may reconsider an application where material circumstances have changed, including policy changes and new evidence, such that the decision-maker is not reconsidering an identical application. 2. Under section 6(2)(f)(ii) of PAJA, rationality requires a rational connection between the material made available to the decision-maker and the conclusion reached. A decision is rational where the decision-maker has considered relevant evidence, addressed material concerns, and reached a conclusion that is logically connected to the evidence. 3. Reasonableness under section 6(2)(h) of PAJA is distinct from and broader than rationality, requiring consideration of factors including the nature of the decision, reasons given, competing interests involved, and impact on affected persons (applying Bato Star principles). The reasonableness test is particularly important where constitutional rights such as environmental rights under section 24 are implicated. 4. An administrative decision-maker must provide substantive reasons for decisions, particularly when overturning an earlier decision. Failure to do so renders the decision irrational as there is no link between the outcome and the evidence. 5. Regulation 41(3) of the Environmental Impact Assessment Regulations of 2010 mandates public participation where an application seeks a substantive amendment or where the environment or rights of others are likely to be adversely affected. An increase in residential units from 358 to 1064 constitutes a substantive amendment requiring public participation. Failure to conduct such participation violates sections 6(2)(b) and (c) of PAJA as a mandatory procedure.