Hi,
Welcome to the community. First, I advise to post anything you need to, test data and code directly into the post, I wouldnt download Office files from the net as security risk.
From what you post, I question the need to transpose the data to find missing periods:
data want;
set have;
if current_date ne lag(current_date)+1 then flag="Y";
run;
So in this example, the lag lookks back one record and if its not 1 day more than the lag value sets a flag. No need to transpose to do this.