I want to make a change to the return trip of a latitude booking where the outbound is already flown. The web site is letting me do this and even offering better prices than I was expected.

However I want to have a connection at YYZ (maybe this is a cry for help) to earn a few extra miles. The web site is offering 2h20 and 2h47 connections but as long as I'm connecting there I would prefer to have extra time. Is there any way to encourage the web site to offer longer connections? I can't do a "multi-city" search because it's a flight change, all I can enter is a new destination.