Merging Partition D: & H:

I got a 120gb SSD which has my OS installed and a 500GB HDD which is split in two, one for games (Spill) and one for software (Programmer)

When I split the HDD into two partition I did not know how many GB each partition would need, so I guessed and of course I guessed wrong.

My question is:

Is it possible to Merge Partition D: (Programmer) and H: (spill) together back to it's original state and then split them again? so that the H: can get lets say 250GB and the other partition 300GB

I've tried writing it as simple as I can, ask if there is something you don't understand - I would really appreatiate easy solutions since I'm not the exactly the best at this.