Ok, I messed up and my PCB, which will have surface mount and thru-hole options, ended up with all the optional surface mount components on the backside.   It's just hundreds of diodes and resistors, and no ICs, so all I need to do is swap every track on the top and bottom layers which will leave all the thru-hole components still connected. I tried selecting a top side track then used Find Similar Objects and set the tracks to Document Layer but that only seems to move the one track each time. Is there an easy way to do this on a global basis ?