No the lease can’t be changed until it runs out as far as I’m aware
In flats, the freeholder would spend the leaseholders money on the communal area. An unscrupulous freeholder could increase these cost for maintenance and upkeep
If a freehold is going to be sold, the leaseholder has right of first refusal.
I used to own a flat years ago and the freeholder was going to transfer to his niece. He owned the freehold and one flat in the building, and he was moving into a retirement home. We as leaseholders complained and so we were allowed to purchase it. In the end he just wanted his legal cost covering, so we ended up buying a 1/6 share of it each for about £200 per flat.