LG Unify External to Internal
Use Link2SD. 


Create a new partition on your SD card, and format it to ext2/ext3/ext4 filesystem.
Take your SD card and mount it in your PC. 
Repartition your SD card into two partitions, one for normal data storage(rest, fat32) and another for the linked apps (4gb, ext2). You can name the partitions whatsoever you wish. 
Now insert the SD card in your phone. Link2SD will detect it and show two partitions under storage. After this, you can refer to Link2SD's own help menu and tutorials. 


You may try GParted for partitioning.