Reduce Snapshot sice

Hello,

I have snapshots from a ticketing system, every week one snapshot. The Snapshot contains ALL data from beginning to today. So lots of the tickets are closed.
At the moment I read all snapshots and combine the snapshots to one long list with an extra column for the week the snapshot belongs to and export this data in another PowerBi Dashboard to do the dashboarding. 
Due to the limitations of exporting data in PowerBi I would like to reduce the dataset sice. The Idea I had is, that I delete all rows from the snapshots if there is entry with the same ticket number and status in a forme snapshot.

Any Idea how to do this?

Regards, 

Tobias