I know how to do it @ForkWNY everyone seems to be missing the point
Not sure if it's different per router type (in my case, GT-AC5300)...to reset a node, login to the web UI. Head to AiMesh > Click on Node to reset > Select "Management" > Remove Node. This effectively seems to pull the node off the AiMesh network by rebooting then resetting the node (same as holding in reset button for 3 seconds). Unless this was a fluke, this was my experience when testing this under the latest GT-AC5300 firmware released a couple of days ago.
I did this to one of my RT-AC68U nodes...removed it via the web UI, which pulled it out of my AiMesh list. Then I was able to "Search" for the AiMesh node and re-add it, as if it was reset. I never used the reset button...once I initiated a removal through the web UI, it appeared to be the equivalent of resetting itself.
Note that this function is absolutely useless if you factory reset your router and don't "delete" your AiMesh nodes before doing so. If you plan on factory resetting your router, I would recommend removing all of the AiMesh nodes first using the web UI, should save you the hassle of using the reset button.
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