Sounds like you haven't wrapped your head around the basics of smart contracts.

Yes, a blockchain gives you an (ideally) immutable foundation. No, that doesn't mean that every transaction that invokes a smart contract has to be immutable. If a smart contract for a particular use case needs to have the ability to "backtrack", so it can, there's nothing stopping it.

Great reply, the rule for thumb of 'anything that can be done manually can be automated' applies here.

Needs backtrack, code it in, then everyone knows how the rules work and there isn't any side deals or exceptions.

Cheers!