Softening up a polyester rope?

I have a canyoneering rope (8.3mm Canyon Fire), which I got for a light weight haul/tag/jug line for the backcountry.  The thing is strong as buckets, durable, but more like a cable than a rope; such a handling nightmare.  It's polyester as opposed to nylon like a normal rope so it doesn't absorb water... anyone have any experience softening up this kind of rope?  Wash or soak it with some fabric softener?

Ask the manufacturer. I wouldn't use any chemicals before asking the manufacturer.

Polyester gets stuff as you use it. Imlay ropes are woven really tight with a cable braid. Hence cable