Can we honor this employee’s request for a pay cut?

Q: “We provide in-home care for individuals with intellectual disabilities and have notified our employees that effective January 1, 2015 they will no longer be able to work over 40 hours per week, since the DOL will no longer allow the Companionship Care Exemption from overtime. I just received a letter from one of my employees offering to take a pay cut so that she can still work 40+ hours per week but make the same amount she is currently making. Is it legal for me to cut her hourly pay rate (at her request)?” – Janet, North Carolina