mv /home/var /var
mv /home/tmp /tmp
Seems simple enough to me.
If you were doing this in attempt to regain some disk space because your /var partition is too small same with /tmp, try using sym links.
Move your /tmp and /var back to /home, but then issue the following commands:
ln -s /home/var /var
ln -s /home/tmp /tmp
The other thing I would check before doing anything period is that /var and /tmp aren't mountpoints for their own partitions, if so, you need to fix your fstab file before moving them.