If possible....cut dates in chunks n' put into saucepan so they will cook down quicker.....add 2-3 cups of water n' stir often (LOW heat)...you can add a bit more water until it cooks down to a nice consistency.
Once filling has cooked down, add sugar n' baking soda...then mix the cornstarch with water n' add it...stirring well. Let filling cool down for about 15 minutes or so, it will thicken more as it cools, then pour filling into the pie crust, smoothing it to the edges of the crust.
Use egg whites( room temp ) for the meringue....adding some sugar a bit at a time, not all at once...about 1-1 & 1/2 tsps....I also add a bit of creme of tarter but you don't have to. When filling has cooled a bit, and once you have formed "peaks" in the meringue....PILE it on top of the date filling, spread it to the edges of the crust....make some nice peaks (can use the back of a spoon).
Into a pre-heated oven at 350 degrees for 10-15 minutes until a nice golden brown...do check though to make sure it doesn't get too dark as most ovens vary in temp. ** This pie MUST be served cold....refrigerate for 4-5 hrs. ENJOY !!