Are your date and end of quarter date variables actually SAS date values or something else?
What do you want the output to look like?
It helps to provide example data in the form of a data step so we don't have to ask a lot of questions about your current data. Instructions here: https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-dat... will show how to turn an existing SAS data set into data step code that can be pasted into a forum code box using the <> icon or attached as text to show exactly what you have and that we can test code against.
If the values are actual SAS dates and hence would sort appropriately:
Proc sort data =have;
by account date;
run;
data want;
set have;
by account date endofquarter;
if first.endofquarter or last.endofquarter;
run;
would have a data set with two records per quarter (assuming there are two or more).
If that doesn't work you need to provide some example data and the desired output for the given data.