Accessing data in console application run as scheduled task

But I need the previous execution employee list in order to check if any change in status has occured or not with the currently retrieved status.

I think you are implementing in wrong way, you are here depending on your application to decide if the status is changed or not

but in reality it should be dependent on your data - your data should be able to tell you if status has changed or not, in anyway storing status in application in not desirable, if application crashes or machine is restarted then you will status will be lost.

is that "web service" written by you or is it third party? if you can create a web service which will give only changed employees then you can achieve it easily. you can track changes in database using triggers.