You can reset it from Lightroom Classic (in preferences->Lightroom CC) or from the Lightroom web interface at lightroom.adobe.com
Thanks I see my 40'000 plus previews on lightroom.adobe.com but how do I erase them/reset the cloud info? Have looked around but do not see this possibility yet.
Thank you for your advice
Click on the Lightroom icon on the top left and select account info.
Thank you that worked perfectly