I wanted to know if it is possible to change the CPU on my Lenovo laptop that has the following specs

You should have
Pentium N3520, N3530, or N3540
All are DDR3L 2.16GHz base clock Pentium for laptops
http://www.cpu-world.com/CPUs/Pentium/Intel-Pentium%20N3520.html
1170-ball micro-FCBGA
BGA = Ball Grid Array = 1170 tiny solder balls attaching CPU to motherboard.
Not upgradable
They only differ by the turbo frequency, so all would be motherboard soldered
http://www.cpu-world.com/Compare_CPUs/Intel_FH8065301616103,Intel_FH8065301728501,Intel_FH8065301919700/
Very few laptops today can get upgrades in either CPU or graphics.
What you buy is what you get.