"On Monday, January 23, President Trump issued a memorandum that suspends the hiring of civilian employees in the executive branch. The Director of the Office of Management and Budget (OMB), in consultation with the Director of the Office of Personnel Management (OPM), is instructed to recommend a plan within 90 days to reduce the size of the federal workforce by way of attrition. The order will expire upon the actual implementation of the OMB plan, though the memorandum does not specify a time frame for when such implementation must occur. On Wednesday, January 25, OMB issued explanatory guidance to agencies on the implementation of the freeze. It stated that workers offered a job on or before January 22, with a start date of February 22 or earlier, should enter their positions. However, those individuals whose start date is after February 22, or undetermined, may have their job offer revoked. Agency heads are given discretion whether to honor these offers."
CRS Legal Sidebar, January 26, 2017
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html