When a recipe has 4 serves how do you make it one?

Halve it and have leftovers.

change amounts  to 1/4th called for   OR make the  full recipe

  place in single serve container and FREEZE the other 3 servings

reducing ones time cooking in the future   aka HEAT and SERVE

Duh, reduce everything by 4 , or better still make the full amount and freeze the rest. Then when you don’t want to cook, get your ready meal out. Much better than shop ready

 meals .

Cut the ingredients down to a 1/4 of the amount.

Or just 1/2 it if your'e hungry or want leftovers.

Reduce the amount of the ingredients.  That is, if the recipe calls for two pounds of pasta, then use only a half-pound

You can reduce the ingredients by four unless it uses an egg - then all bets are off. Better to make the recipe as written and freeze in single serving sizes. No more work than making one serving and you have 3 more servings the take NO work saved for later.

Divide the ingredients needed by 4.

If it calls for 1 cup of something, you would use ¼ cup of that ingredient. 

Most recipes are geared towards (a family of) 4. Many online recipe sites can reduce the recipe to one person, but many times it will give you a strange amount of ingredients (like 1/32 teaspoon-good luck measuring that). Probably your best bet is to just reduce the protein by 3, and judge the seasoning, rather than trying to measure it out. 

If a recipe contains a gravy, just make what it says-too much gravy? Oh well-make mashed potatoes and use it up that way. 

Eat the whole thing, or divide the amount of each ingredient by four.

I suppose it depends on how hungry you are.