This is how the DOJ stated it:
In August 2015, the Chairman and Chief Executive of Corporation-1, a media company that owns, among other things, a popular tabloid magazine (“Chairman-1” and “Magazine-1,” respectively”), in coordination with COHEN and one or more members of the campaign, offered to help deal with negative stories about Individual-1’s relationships with women by, among other things, assisting the campaign in identifying such stories so they could be purchased and their publication avoided. Chairman-1 agreed to keep COHEN apprised of any such negative stories.
Consistent with the agreement described above, Corporation-1 advised COHEN of negative stories during the course of the campaign, and COHEN, with the assistance of Corporation-1, was able to arrange for the purchase of two stories so as to suppress them and prevent them from influencing the election.
First, in June 2016, a model and actress (“Woman-1”) began attempting to sell her story of her alleged extramarital affair with Individual-1 that had taken place in 2006 and 2007, knowing the story would be of considerable value because of the election. Woman-1 retained an attorney (“Attorney-1”), who in turn contacted the editor-in-chief of Magazine-1 (“Editor-1”), and offered to sell Woman-1’s story to Magazine-1. Chairman-1 and Editor-1 informed COHEN of the story. At COHEN’s urging and subject to COHEN’s promise that Corporation-1 would be reimbursed, Editor-1 ultimately began negotiating for the purchase of the story.
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There is no mention of anyone "summoning" Pecker to Trump Tower in 2015. Pecker and Cohen got together and came up with the plan on their own.