Going Out
A player goes out when they discard or meld the last card in their hand. This isn't as simple as it sounds though. A player is not allowed to go out
unless they have completed at least one canasta or will complete a canasta in the process of going out. Although not required, it is usually a good idea for a player to ask their partner before they go out in case the partner has a lot of high point value cards in their hand that will count against that partnerships score. However, the partner's response can only be a yes, no or I wouldn't advise it.
Going Out "Concealed"
Going out "concealed" occurs when a player can meld their entire hand, including at least one canasta, without having previously melded cards or adding to their partner's melds. If the player's partner has not made the initial meld, the player who is going out concealed must also meet the minimum count for the initial meld, not including the canasta bonus. I think this is the most logical way to go about this, but the rules on the US Playing Card website differentiate between having picked up the discard pile and not when it comes to meeting the initial meld. If you are interested in this version, I would suggest reading up it on the US Playing card website. Going out concealed is a very tricky thing to accomplish, but will result in an extra bonus, and most likely lots of points against the partnership. It can, however, backfire and a player who has chosen to hold their cards can be stuck with a lot of points against them if the other partnership goes out before the player goes out concealed.