Content type 'Document' - Template delete by error

Hi everyone,

I did a mistake and changed the template of the Content Type 'Document'. And as the option 'apply to child content type' was set to 'yes', it did change the template of all content types inheriting from this default content type 'Document'.

For the content types I have created, it's ok. I changed the template back to what it should be.

But, what about the default SharePoint content type such as 'Wiki page'? How to set it back to what it originally was?

For info I'm in SharePoint online.

Thanks for your help

Géraldine