The 1098-T is only any informational document. The numbers on it are not required to be entered onto your tax return.
However receipt of a 1098-T frequently means you are either eligible for a tuition credit or deduction or possibly you (or your student dependent) has taxable scholarship income. So, you don't need to file an amended return just because you got a 1098-T. But will need to amend to claim a tuition credit or report scholarship income.
Tuition reimbursement is not reported, per se, on a form 1098-T (it may be reflected in the difference between the numbers in boxes 1 & 5.) Employer provide tuition reimbursement is tax free, up to $5250, and is usually included on your W-2.
