Regarding canceling the FSA, the only time that an employee can cancel their FSA account is within 30 days of the effective date or if they have a qualifying event.
Here is a link of the qualifying events that I found: https://www.benefitresource.com/blog/election-change/.
Employees can access their FSA funds by using their FSA Card or requesting a reimbursement on their portal. The employee should log into the portal, but we can also request a card for them if needed.