I pledged several EOS and voted for several people respectively. How do I recover these votes after I cancel pledging some EOS? Are the votes obtained by more than one person recycled in proportion?
It depends on whether you staked those tokens or you deposited them into REX.
If you use a wallet like Anchor to login to an application like bloks.io, you should be able to browse around and see your balances both that are staked and in REX. Find which one they are in, and remove them from that system.