Is it possible to partition the harddrive with a second installation of MacOS, and then delete the original partition? I'm currently on 10.10.5 and I want to partition my internal SSD into two, installing a fresh copy of 10.12 on the second partition (while keeping 10.10.5 on the original partition). I want to eventually delete the original partition on the SSD that the mac shipped with (10.10.5), leaving only the second partition of 10.12. 

Doing a search, it seems it may not be possible to make a second partition the only partition.

Will Disk Utility allow me to delete the original partition? and will it allocate the full amount of regained space to the new partition?
I've solved this problem by taking a completely different approach. I used Disk Utility to clone my internal SSD onto a new partition on an external SSD. I am now going to restore my internal SSD back to factory (by restarting, then CMD + R), then update it to 10.12. This way there is only a single partition with a fresh install of 10.12 on the internal SSD. I will still have my old bootable install of 10.10.5 and files on the external SSD, in case I need to access files or restore it back completely.