Internal Revenue Code Section 501(c)(3)

What happens if a tax-exempt organization becomes ineligible to sponsor a Section 403(b) Plan because it loses its exempt status under Internal Revenue Code Section 501(c)(3)?  As an example, loss of tax-exempt status may occur automatically if the organization fails to file an annual Form 990 information return for three consecutive years.  It may also lose its exempt status if the IRS revokes or terminates exempt status for other reasons.