Bennett Read Mixer - How do I release the accessory hooks/beaters

I purchased a Marvello 10 mixer, which looks like a good product. After reading the manual front to back and watching an online video, no where does it explain how to release the mixer accessories, eg dough hook. It clearly explains how to install and click in the different hooks/beaters but not how to release them. I have tried phoning the customer help line, the mailbox is full. I would appreciate it if someone can contact me to assist.