Rock the cinch. I did it the other day to change the load direction on my TIP. It is a nifty trick and it eliminates falling to your death from going over a basal point. Just remember to untie it on the way down.
These pictures are the before (canopy access base tie), solution (butterfly and quickie to a lead opposite the direction of my work), and result (a reasonable direction to load this mature silver maple lead that had a funky union and lots of storm damage that I needed to get to).
It's not the same as scenario as yours, but the technique is solid. It's much quicker and easier than having your line untied and pulling it up to reset with a predirected canopy anchor.