Swap partitions between /home and /var

I have a server with 2TB (Raid, 2x2TB), and this partition schema

/ => /dev/md2 - 20GB
/home => /dev/md3 - 1.8TB

This is a ISPConfig server, so we need many space in /var and almost nothing into /home, so i think that the best way to do this is put /home in /dev/md2 and /var into /dev/md3

My fstab is this:

# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/dev/md2        /       ext4    errors=remount-ro       0       1
/dev/md3        /home   ext4    defaults        1       2
/dev/sda4       swap    swap    defaults        0       0
/dev/sdb4       swap    swap    defaults        0       0

Which is the best way to do this? I think move /home contents to /homeold, remove from fstab, umount and now copy from /homeold to /home, and then change /var name (i dont have enough space to do the copy), mount new /var and move content, is this correct?

Also, i need to stop all server services to avoid errors (mysql, apache, mongodb, named, etc), any fast way to do this? Or maybe i should restart in rescue mode to do this?

Maybe another way is a full change between / and /home, i mean, put / in /md3 and /home in md2, is this possible only by edit fstab and reboot?

Thank you sou much,