Can I file an amended return for this year after already completing my taxes? Do I need to repurchase Turbo Tax? This was an employer error.

You do not say what the employer changed---so it is not clear whether you need to amend.  What did they change?

Hi - Thanks for replying - apparently the error was on our group term life insurance - Group term life insurance is a benefit provided by employers that covers employees and their dependents. The premium becomes a taxable benefit when the coverage amount exceeds $50,000.