First, you should check for instructions on the developer's website. Most likely you will find available versions for your tablet there but if there is no information on the support section of the manufacturer's website you can update it or flash another version of Android using custom ROMS. Note, however, that this is often a complicated process and in most cases it voids your warranty. It also may result in your device becoming a non-functional slab if something goes wrong. If you're still up for it, search the XDA forum for topics containing complete instructions on unlocking the bootloader on your device and flashing a custom ROM, as well as for the selection of custom Android ROMs compatible with your device.
You should use that forum to ask questions because of the high number of Android developers available. You will get answers pretty fast.