I can't seem to find the answer to this question either on bitcointalk or elsewhere on the internet.

When Eth goes proof of stake, is there already in existence a designated wallet from which holders can stake it?  At the moment I'm holding my Eth in a hardware wallet but I'm sure I wouldn't be able to stake it from there.  Does anyone know about this and perhaps have a link, or is this something that is so far unknown?

I also can't find an answer to when the pos change is supposed to be made.  I saw a thread about this earlier but there was no link and my searches turn up old articles.  Thanks.

Risk Aversion: Ethmining rewards can be stored in cold offline wallets. Ethstaking deposits and ethminting rewards, on the other hand, must be allowed to mature in an open wallet. With the potential for draconian penalties and the prospect of prolonged ether-at-risk exposure, many average or risk-averse ETH holders may stay away from participating as a validator. Also, those with more to gain by “gaming the system” are more strongly incentivized to join as a validator during the early part of the Casper rollout. The risk aversion problem is expected to be mitigated over time as more and more potential ethstakers see the success of the proof-of-stake security and observe how Ethereum staking works.