Yes - they can resign -I just said I had a few issues and needed to spend more time with my family. Some of the other elders tried to get me to change my mind but by then I was absolutely PIMO and knew it wasn't the truth.
no-zombie is correct - almost overnight my status had changed from someone always involved in the meetings , giving talks at assemblies etc to zero - I wasn't even doing microphones! Our social circle changed - suddenly the occasional meals or drinks with other elders stopped and the rest of the cong viewed me with some detachment. I remember sitting in an incredibly boring meeting hearing the GB being venerated and wondering what on earth I was still doing there. That was my last meeting (other than a Memorial as my wife was still attending.)