Repair Jetvac JV-105 hose

The second section of hose has split near the junction of the first hose section (White) and the second section (Dark Blue). I tried to separate the blue hose by holding the male connector and turning the plastic nut. It only keeps on turning around. How can I remove the nut and cut the split hose part, then replace the remaining hose to the first section?

Thanks Edog

I don't know anything about those units, but I'll move your post into the correct section.