Just remove the cap bolts on the cam you want to remove. Leave the other cam caps alone.
You have nothing to lose trying to remove the exhaust cam only because if it does not work you will simply have to remove the intake cam as well. I do think I always had to remove the intake cam first though to get enough slack in the chain to remove the exhaust cam. I may just be associating that sequence though and it is not really nessasary. In the end, don't remove any more cams than you have to as it will just make the job take longer with absolutely no gain at all.
Brian
If you are removing only the exhaust cam to change shims should all cam cap bolts be loosened in the prescribed sequence or can the sequence be changed to include only the exhaust cam caps?