Conservative lawmakers want any bipartisan effort to stabilize Obamacare’s markets to include flexibility on the law’s requirement that people buy insurance or pay a penalty.

Sen. Lamar Alexander, R-Tenn., is set to address Republicans at a caucus lunch Tuesday on the bipartisan deal he is working on with Sen. Patty Murray, R-Wash. Alexander has been working to reach a deal to pay insurer subsidies in exchange for giving states more flexibility with Obamacare’s regulations.