When you work for an employer who offers a 401k, it often makes sense to contribute as much as you can toward your retirement. By putting money into a 401k, you may also qualify for matching contributions from your employer. If you change jobs or get fired, you will need to address the money that is in your 401k at that point. You don't want to simply leave the money behind, as you would lose out on all of the savings that you set aside.401k RolloverWhen you leave your job, one of the options that you have is to engage in a 401k rollover. This is a process that involves transferring money from your existing 401k over to a new retirement account. For example, you could transfer the money from your 401k to a new 401k at a new job. You could also transfer the money from your 401k to an IRA or a Roth IRA. If you transfer the money to another 401k or a traditional IRA, the money will retain its favorable tax status. If you transfer the money to a Roth IRA, taxes must be paid on the money because it uses a different tax status.How it WorksWhen you are interested in engaging in a 401k rollover, the process is generally quite simple. You start the process by opening a new retirement account such as a 401k or an IRA. Then you notify your new account provider that you are going to be rollover funds from an old account. You then go back to your old provider and request a rollover. You will then have to fill out a form for your old account provider with information about your new account. At that point, your old provider will send the money from your old account to your new retirement account.ConsiderationsIf you are considering simply taking the money out of your 401k after you quit your job, you could use up a lot of your retirement funds. When you take this approach, you have to pay a penalty and pay taxes on the money, which will really eat into your retirement funds.