Q : How do I pull in the same advertiser into two different sized zones

I have a page with a wide top banner and a tower banner. Each advertiser has both sizes. I only want one advertiser on the page at a time. How can I do this?

 

A : Add those two banner ads under same campaigns. For example create Advertise 1 --> Campaign 1 --> 2 different size banners. Likewise for another advertiser.
While creating/updating check the option as "Companion positioning", from this ad deliver from one camping on top zone and in bottom zone ads will show from same campaign.