There are yeast cells in all volume. Very little of them in liquid, a lot in settled down layer. More on the top.
If you only need to wait a week or so, just discard the liquid and pitch. If you need to wait longer, I would strongly suggest making a sterter.
Starter or not, I would suggest you to take jar out of the fridge day before use, swirl it to make content homogeneous, and put in fridge again. That way, when yeast cells will settle down again, you should see 3 layers. Liquid, bright live yeast, and darker dead yeast. If so, of course use only the middle layer. But if you can see only two, that's OK, too. Discard liquid and use what's left, take from the top how much you need.