I contact the schedulers directly. If I reschedule they do not report the shop as cancelled.
I've performed many shops via ISS, have great ratings, but still am limited to accepting no more than 3 shops at any time. I have to complete one before I can add another.
My posts are solely based on my opinions and for my entertainment, contact a professional if you need real advice.
When you get in debt you become a slave. - Andrew Jackson