softupdates, adding space to partitions, etc

[Comrade Burnout]

I just noticed that I didn't create *quite* enough space in my /var 
partition for accepting somewhat larger email attachments/ messages.

i thought softupdates was the way to go, but on reading the handbook 
online, that's not quite what i thought it was ....

is there any way with 5.2.1 to move around disc space between partitions 
"on the fly" ?