These transportation pretax accounts come with a risk. You can forfeit the funds because you are not supposed to use them after your last day of work. You can't get a refund, and you can't convert them.
Most programs place the funds onto a card that can only be used at specific types of businesses. The local mass transit system actually knows which funds ...
A.) Move these funds back into my paycheck (I understand this would come with a standard income tax rate and a penalty),
So from what I can tell from:
26 CFR § 1.132-9 - Qualified transportation fringes.
Q-14. When must the employee have made a compensation reduction election and under what circumstances may the amount be paid in cash to the employee?