If the purport of a void legal act is quite similar to that of a legal act that is valid, the void legal act could be replaced by the valid legal act. This is called conversion and is laid down in the Dutch Civil Code. It is required though, that the involved parties would have opted for the valid legal act above the void legal act.
The rationale behind the conversion is to prevent that the nullity of a legal act would have a larger effect than is justified by its purpose.
A legal act is null and void if:
Conversion will not take place if this would be unreasonable to any party concerned who has not cooperated in the legal act.