You can adjust the dining plans up to 3 days (72 hours) prior to your check-in. After the 45 day mark, there can be a change fee (~$50 I believe), but it's typically waived for upgrades, though downgrades are usually charged it. Inside of about 10-14 days, this fee is typically charged for any changes and may even increase.
So, it's still possible to remove or downgrade the plans at this point (up until Monday), but do expect a change fee to be incurred. The refund of the money spent on the dining plan may also take some time to be processed.