When you leave your current employer, if the balance in your 401(k), or what's left of it given what's going on in the market

, exceeds $2,500 you may roll it over into an IRA at virtually any brokerage. The advantage of doing this is that you can manage your 401(k) investments in one place along with any other taxable investments you might have at another financial institution. This way you get to choose investment options that may not currently be offered within your 401(k), too!
The second advantage is that most 401(k) plans offer ridiculously expensive fund choices, and rolling your money over into a Rollover IRA with a low-cost investment manager or brokerage such as Vanguard or Fidelity (as long as you meet fund minimums) for instance would make your investment expenses considerably lower than what they might be now. You have the choice of liquidating your 401(k) and using the proceeds to buy similar (often cheaper) funds and transferring the shares in funds currently in your 401(k) "in kind" into a Rollover IRA. I would recommend liquidating and buying into a similar fund over an "in kind" transfer.
If need be, you can also withdraw money from your rollover IRA to meet eligible educational expenses. You'll pay income tax for sure, but you won't be hit with the 10% penalty the IRS levies on other early (i.e. before you're 59+ years old) distributions from IRA accounts. So it's also a somewhat decent "worst case scenario" backup for MBA funding.
disclaimer: I have all my money at Vanguard and will shill for them at every available opportunity