I'm not powering down, I never did.

"I'm a bomb technician, if you see me running, try to keep up" ;-)

Witnesses are paid in SP for the blocks they are signing so the only way to use block production rewards to pay for operating cost is to power down.

As for changing account recovery partner - please note that such account (in vast majority of cases it is steem) doesn't have any special privilege except for account recovery, but even then, they can't change your account keys, all recovery partner does is to "tell the blockchain" if your account recovery attempt is legitimate or not to their knowledge (and Steemit Inc does that basing on details that people provided during singup, such as their e-mail address)