I'm trying to fix a Kitchenaid KUDC210s2, and can't seem to figure out how to remove the lower spray arm. I had a service person out to repair it, he removed it, removed the strainer (for cleaning), then (for whatever reason) re-installed it without the strainer. When he went to remove it again, he said he couldn't, that it was stuck. I would just believe him, except he was fairly incompetant. I have since repaired obvious issues with another dishwasher that he had allegedly fixed. Is there any sort of clip or fastening device locking it? It spins and moves freely, but won't lift off. The underqualified serviceman that caused this problem in the first place said, "it should just lift off." However I can't imagine that it just sits there without any restraining system whatsoever. Any help you can give me in this is greatly appreciated.

Any idea what I may be able to do to remove it?