What is the ruling on money taken from a Hindu if it is known that this money was collected to offer to an idol?

If "change" means exchanging a banknote for its smaller denominations, this transaction is originally permissible, provided that the parties do not separate before all the money has been taken possession of. However, since the money in return is forbidden because it was collected to offer to idols, this transaction is not permissible. You must return the change and take your money, unless that is impossible because the money has been spent or they have disposed of it.