I would not advise a client to do this. From the PTE:
IBM stock ≠ cash. When I get questions from clients about in-kind transactions (typically contributions), upon questioning I find that the motivation is a mistaken belief that they can avoid reporting a gain on the asset. When I tell them even if permitted, it is treated as a taxable sale and the gain will be taxed, they lose interest.
Refer him to legal counsel.
If you are still employed then this was likely an error which you should discuss with both your employer and the plan service provider to have rectified (i.e., repaid to the plan). You didn't mention any 20% tax w/h attributed to your balance, which further makes this look like a mistake. David's comment above only applies if you no longer work for the plan sponsor.
At least for an individual-account retirement plan and for a non-owner participant, a participant subject to an involuntary minimum distribution (after the later of when the participant attains age 72 or retires) presumably ended employment and likely attained the plan’s normal retirement age. Such a participant likely is entitled to a distribution.
Following C.B. Zeller’s note, isn’t the real question whether the plan’s provisions allow such a participant to take an amount less than her whole balance, or instead require that a voluntary distribution be a single sum of the entire account?
And aren’t the answers to many questions found in the realm of RTFD—Read The Fabulous Document?