I'd like to resize an existing LVM partition and add the space to another LVM partition.

```
[root@dckapstaging ~]# df -h
Filesystem                           Size  Used Avail Use% Mounted on
/dev/mapper/vg_dckapstaging-lv_root   50G   50G     0 100% /
tmpfs                                3.9G     0  3.9G   0% /dev/shm
/dev/sda1                            485M   91M  369M  20% /boot
/dev/mapper/vg_dckapstaging-lv_home  215G   93G  111G  46% /home

```

I want `/dev/mapper/vg_dckapstaging-lv_root` to be extended to another 15 GB from `/dev/mapper/vg_dckapstaging-lv_home`; how can I do it?