I'm upgrading from a 120gb PNY SSD to a 500gb Samsung 850 SSD. 

I cloned the 120gb SSD using EaseUS Todo Backup onto the larger SSD, but it seemed to copy the setup of my smaller drive, so on my larger SSD, I have 354GB that is unallocated. 

How can I merge the primary partition and the unallocated?

![disk properties view][1]

![Disk Management view][2]

When trying to extend the volume via Disk Management, I get the following message:

[![Disk Management extend volume][3]][3]


  [1]: https://i.sstatic.net/riDJe.jpg
  [2]: https://i.sstatic.net/uNcYb.jpg
  [3]: https://i.sstatic.net/XThPC.jpg