How to resize the base of a stock swiss lace hair system?

[Hair2018]

So I recently got my first hair system - (a partial, stock swiss lace). I went to a stylist who has her own salon and is experienced with hair systems. She resized the system by cutting the base down to size to fit over my balding area, then did the fitting and cut in. I did not see what she was doing when she resized the base.

However unfortunately she lives quite far from me and I do not want to keep spending time and money to have bases resized. Could anyone tell me how to resize the base of a lace hair system? I presume you just use scissors or a stanley knife and leave the hair hanging off the sides and don't cut hair while resizing the base, but I need to be sure how to do this. I have also heard that you should not cut the hairline of the base, as this will ruin the bleached knots/graduated hair density and not make the hairline look natural.

I want to have the option to be able to comb my hair back (exposed hairline) and forward (unexposed hairline with fringe) depending on whatever style I feel like having on any particular day.

I should add that I am going to order a custom hair system next, but if I ever order a stock system in the future (for example as a backup), I would prefer to save money by resizing the base myself. Surely it cannot be that difficult.

Thanks.

[grincher]

An all lace base is important as a a cut poly can leave the hair looking unnatural.
Leave the hairline and cut behind to size. You should use hair clips so the reminding hair isnt cut.
You might want to create a template and cut your stock to that size or slightly larger and then reduce slightly as needed.
Alternatively, use a template to create a correctly sized piece as I do. Custom made will always look better.