Replacing Lubuntu with Ubuntu

I installed Lubuntu 16.04, and noticed quite a few bugs. I want to remove this OS, and put Ubuntu 14.04 on instead.
When giving the Linux partition back to Windows, I understand that you need to put the Windows 10 .iso onto a flash drive, and repair Windows from there.
However, I don't want to give the partition back to Windows. I want to delete the Lubuntu volumes from disk manager, leave it unallocated, and put Ubuntu in it's place. Is this possible? Or do I have to give the partition back to Windows, then re-partition it for Ubuntu, and then install Ubuntu in the re-created unallocated disk space?
Thanks!