In Dark Souls 2, summons/invasions depend not on levels, but on the memory of souls, i.e. if your soul memory is 20 thousand, and your friend’s soul memory is 200 thousand, then you will not be able to meet him in the game. The trainer allows you to increase or decrease the memory of souls.

F1 - increase soul memory by 50000

F2 - lower soul memory by 50000

For players who play pirates, this cheat is useless, because the memory of souls is taken into account only for those who play online