Convert shared region to Collection when original page has gone

I've converted a site to Runway and all the pages are now In Runway. Great!

I want to import a shared region into a Collection. I can only do that if I unshare the region, that's correct isn't it? However, in this case, either I have deleted the original page or it is now in Runway, so I cannot unshare the region. Is there a way round this that would allow me to import into the Collection?

Thanks