Through parliement. Thats just how a normal democracy works. Or through a referendum.

unless we are talking about handling a national crisis, or avoiding a US-style shutdown, then avoiding a vote may be legitimate under specific circumstances.

but I doubt pension reforms fall under national emergencies

I agree it should not fall under national emergencies, but I don't see any other way it would pass. Nobody wants to work longer for no gain. The pension system in a lot of countries is basically a ponzi scheme.