How would I draft an email to all employees letting them know of the changes in the number of days off per calendar year?

Matters like "changes in number of days off per calender year", applicable to all the employees, form part of a company's rules, regulations, and policies. Information on such matters needs to be incorporated in company's systems and procedure manual.

Intimation to all employees on such matters can follow one of the two patterns. In first pattern, the the changes are incorporated in the basic manuals of the company independent of the intimation to individual. In addition intimation is given to individual employees of such changes giving appropriate reference to the part of the manual affected by such change. In the second pattern them the intimation to individual employees it self constitutes the document effecting the change in manual, which is then attached by employees to copies of manual. Maintained by them.

With the use of on-line manuals in many companies, it is perhaps not necessary for individuals to maintain individual copies of the manuals, and we can assume that the email communication referred in the question is of the second type - that is, its primary purpose is to inform rather than constitute a formal document covering all detailed contractual aspects between the company and its employees. In a case like this the email could have a format similar to one given below.

Sample format of an email intimating change in changes in leave rule.

From: Human Resources Department

To: All employees

Subject: Leave Entitlements

Please not that with effect from ................., the leave entitlements of employees has been changed from .... days per year of service to ....days. For complete details of the leave rules please refer to Section .... of the company's Employment Rules Manual.

(HR Manager)