Dest alt going below planning minima?

[president]

Assuming EU-ops. You are en route to your destination when your destination alternate airport drops below planning minima but remains above operational minima. From a legal perspective can you still use it as destination alternate or do you need to pick another destination alternate. My opinion is that you can still use it as planning minima apply only in the planning stage. But I need documentation and reference to where I can find it in writing. Not just personal opinions.

Thanks!