If the laptop contains 8GB of RAM and it will be probably using two 4GB strips of RAM that too in separate slots. The way memory fits in the laptop or computer is the main aspect here.
It's so quite easy to remove and expand the ram. But one of the most common ways to upgrade the RAM in a laptop or computer is to replace the whole 4GB strips with 8GB strips. That's where the problem solves. By giving your laptop a total of 16GB.
Image Source-Google.com
But it can be a long process to do. You can sell the old laptop and purchase a new one with 16GB RAM.