verb

acknowledge (a significant or happy day or event) with a social gathering or enjoyable activity.

they were celebrating their wedding anniversary at a swanky restaurant

commemorate,observe,honour,mark,salute,recognize,acknowledge,remember,memorialize,keep,drink to,toast,drink a toast to,enjoy oneself,make merry,have fun,have a good/wild time,rave,party,have a party,eat,drink,and be merry,revel,roister,carouse,kill the fatted calf,put the flag(s) out,step out,go out on the town,paint the town red,whoop it up,make whoopee,junket,have a night on the tiles,live it up,have a ball,push the boat out,jol,spree,go on a spree,rollick