It depends on which model you have. ALL Celeron model lacks a SATA interface, so you're stuck with the 32GB of soldered eMMC. The SATA Pentium board doesn’t have this problem, but you need to replace the board, buy your own RAM (DDR3L) and a hard drive with matching caddy. Anything will go here, but you cannot expect there to be eMMC or RAM included on these boards.

Some Pentium models include also use eMMC, which has the same issue as the Celeron board. If you absolutely need more then 32GB, sell this to the highest bidder who is okay with eMMC and soldered RAM. It will cost less to buy one with the right board then to replace yours.