Used to be, it was not too much of a problem for an employer to find some way to keep your TS at least for a little while… assuming they had some contract somewhere that needed TS, even if you were not working on it. But they are tightening the rules and that is not quite so easy anymore, or at least they will catch on faster that you have TS but don’t really need it.
As long as your adjudicated eligibility for TS remains current (two years?) it should be pretty easy to reinstate the TS. But in your situation, you’d only have the “active” Secret.
sbusquirrel explained it best, but its kind of like use it or lose it. As long as you are in a position that requires that level clearance then it stays but if you take another position that requires a lesser clearance then that is what your clearance will become. If you dont need it you dont get to keep it at least that’s my understanding…and I could be completely wrong but that is how it was explained to me. Ill give you an example of me from several years ago…I had a TS/SCI, went to another position where SCI wasnt needed so I got read off of my SCI but keep a my TS. Another example is when I retired from the Military I had a TS/SCI…I took a DOD contracting job that only required a secert…My TS/SCI…went to a secert because I was not in a position that required that level of clearance.
Jobs have clearances, you only have the eligibility to work the job. The work that you are assigned is Secret, you will have a Secret clearance. You will remain TS eligible for some period of time but will no longer have access at that level.