I'm posting this because of something I saw in an online group. Some members clearly misunderstood the situation, and if they did, it seemed likely others will too.
When you sell rights (any rights from single use to all rights) you generally sell them to the company who own the publication – not the magazine or the editor. The rights you sold will belong to that company for the term of the agreement (which is usually the whole copyright term, so long after your death). This will be stated in the contract.
You don't get those rights back if the editor moves on, or the magazine closes, or it was such a long time ago you think it doesn't count anymore. The only way you can regain your rights is to buy them back – and whoever bought them is under no obligation to agree.
Please, please, please don't sign any contract until you're sure you understand all of it completely, and that you agree with the terms offered. And keep a copy! Don't assume you'll remember, and don't assume you can ask another writer to check for you – they may well have been offered different terms, especially if they signed at a different time.