They did let you cash out back in the early 1990's, with some restrictions.
There was a dollar limit on the computed present value of your future pension payment cash flow, which means interest rates play a role in calculating that. With interest rates looking to rise, the computed present values will probably fall over the next year or two. This may allow you to meet their criteria if you can cash out the plan.
You also do not have to take it right away. As I recall, we could decide on it anytime up to a year or two after leaving. Maybe even longer.
You have to role it over into a self directed IRA, or pay penalties and taxes.
Hope this gives you the basis for asking questions about it at HR. Remember, my info is 10-years out of date.