Reemployment After Retirement

Dear all,
my boss has asked me to draft a letter for employing a retired person as trainer/ advisor. does any one of you has a format for the same..

also what should be the terms and conditions for such employment

Hi,
Please try Cite HR archives.
Type “.Hiring Retired Employees.” inside the box ‘Search Cite Co’
that you find in the title bar right above.
After typing in the box, press the 'research' button next to it.
You will get lot of information.
You can also try with alternate descriptions.
V.Raghunathan