Per changes to the IL Condo Act (effective in January), any owner who is more than 60 days delinquent in paying assessments does not need to be counted toward quorum requirements for any meeting called to review and adopt an amendment to the Declaration or By-Laws.
If your association is having difficulty achieving the necessary quorum to vote on an amendment to your governing docs due to absentee or non-participating owners and those owners are more than 60 days delinquent, you may remove their percentages from the total in order to calculate the new quorum requirement.
An example:
Percentage required to establish a quorum: 50%
One unit owns 20% and is 60 days delinquent.
New percentage required to establish a quorum: 50% of 80%, or 40%
The delinquent owner can still vote at the meeting if they do show up, however. Keep in mind that this change is specifically in regards to voting on an amendment.