The best way to decline a job offer after accepting it is to send a certified letter in the mail. Save a copy of the letter and the delivery receipt for records. A telephone call or email to the company is recommended as an extra measure of courtesy.
When declining a job offer after initially accepting it, act as quickly as possible to minimize the inconvenience for the hiring company. Sending a paper letter with delivery confirmation leaves a clear paper trail that proves the date of and reason for the decision. Forbes Magazine recommends keeping your letter short and emphasizing your gratitude for the job offer. A phone call prior to the receipt of the letter is recommended for time sake. Use a respectful approach and a neutral, professional tone regardless of the reason for the decision. The goal of this strategy is to preserve goodwill and avoid damaging relationships with existing professional contacts.
Declining a recently accepted job offer is often embarrassing and awkward, but without a signed employment contract, the approach is appropriate. If there is already signed a contract, read it carefully, and search it for information about employee rights and responsibilities with regard to resignation. If the contract is unclear, consult an attorney or an authorized representative from a labor union.