You only report what was paid in the tax year. Box 1 on a 1098-T should report that.
If your 2017 1098-T used Box 2 (what was billed) and you used that for a credit, you may need to amend for 2017 if you received a credit based on expenses billed but not paid in 2017.
For 2018, if the scholarship posted and was paid to the school for tuition, the amount should also be in Box 1. If the scholarship posted in 2018 and went to pay for room and board, you will need to claim that amount as income on your 2018 tax return.
Compare your school account statement to your 2017 and 2018 1098-T. Adjust if necessary by using the "What if this is not what I paid?" link under Box 1 on the 1098-T screen, and/or allocating scholarship funds to different years.
