The phrase "new dialog" means having a fresh and different conversation or discussion. It suggests the start of a new way of communication or exchanging ideas. Full definition
There are also new dialog lines in the case that the hero is not in the party, if the game has been completed. (dragon-quest.org)
Development of the brand new dialog transactions to coordinate field service engineers activities and service support call centers. (jobhero.com)
I'd like to point out to you, however, that Howey is leading a difficult and potentially critical new dialog within the non-aligned author corps. (thebookseller.com)