For this reason, it is common for many companies to write contracts that employees must terminate at least a month in advance upon termination. If employees sign the contract, they must comply with it. If your employer doesn`t agree, but you still want to leave prematurely, consider whether it would cost them money. For example, if they need expensive agency staff to replace you in the short term, they could take you to court. If you have read these terms, you will often notice that some companies that operate online try to reserve the right to change their online terms at any time without notifying the site user. For example, Yahoo! warns its users in the first paragraph of its Terms of Service that the Terms “may be updated from time to time by Us without notice.” .