It depends by what is meant by "error":1) If they mean that the amount was discretionary and they simply have re-thought the amount they want to issue you, they can't change that once the check was issued and deposited: merely wanting to change their mind does not let them "call back" money they already paid you.2) But if there was basically a mathematical error in what was a known formula for determining your severance, they can correct that error: the law may not allow peoplet change their minds about this, but they can fix typographic or mathematical errors. So say that the policy in your company, and what you were told, is that they pay 1 week severance plus 1 week per year of service, and you worked there 5 years. You should therefore get 6 weeks severance. If someone accidently gave you some other amount (e.g. 7 weeks), they could recall that check and issue another, to correct a mathematical error in a formula known to you.