One way is to lower original gravity. You do that by reducing the amount of grain in your mash (or malt extract for that matter)
If you still have too much I guess one would say you could drain a bit of your mash, and then add back water, so you dilute it.

Ofc, doing so will also reduce the amout of fermentable sugar, and as thus reduce the alcool% in your final product.

A terrible way to do it would also dilute with water your final product, but yeah...
Whatever works for you I guess.

Disclosure, I'm still also learning the ropes, so you may get a better advice after mine.
+ I'm terrible at remembering jobs, so I'm not even sure what are your other request for this very job of yours.