If there are important duties which cannot be dropped, please assign someone to take care of them in your absence. You cannot help being sick, but it is still your duty to ping someone and ask them to take over in your absence so that we don't drop the ball. To be clear: you shouldn’t work when sick or otherwise indisposed, but it’s not OK to just disappear and have clients show up to ghost-town calls etc. Don’t work, just be sure to take a minute to assign someone to take over while you’re gone, and cancel what needs cancelling. See Crossover Person Protocol. (In emergencies, this might not be possible, so use your common sense, no one expects you to manage your calendar while you’re being airlifted after a skiing accident – the exceptions to this rule should be pretty obvious.)