natd -redirect_port question

[Laurence Sanford]

I have natd set up on a 4.10 box to get the rest of my network on the 
internet. I have an application that requires connections to be able to 
be established on a specific port. The problem is, sometimes I run this 
app on system A and sometimes on system B. The port stays the same. So 
in my rc.conf I have included in natd_flags -redirect_port tcp 
systemA:port port ; currently if I want to use the app on system B I'm 
having to reboot the natd box. Obviously this seems silly, however, I've 
found that trying to reset this information using a command line like: 
natd -n dc0 -redirect_port systemB:port port results in an errror 
stating redirect can't bind to that port, because it's already in use. 
I'm convinced I'm overlooking an easy way to change this redirect on the 
fly without having to reboot the natd box. Anyone care to point me the 
right direction? Thanks in advance.