Changing a primary or secondary server IP address

[Jason Currell]

I'm wondering if anybody knows how to change the ip address of a primary 
or secondary DNS
for example if you were moving ISP's and therefore are going to be given 
a new IP range.
Do I have to change the DNS IP with every domain registrar for every 
domain that I own or can
I get away with just making one registrar change to the nameservers 
domain only.

eg. Right now I've got the domain's nettwerk.com and werkshop.com 
registered with Netwerk Solutions.

Domain:         nettwerk.com
Primary:         ns1.nettwerk.com   209.17.154.2
Secondary:    ns2.nettwerk.com    209.17.154.1

Domain:        werkshop.com
Primary:        ns1.nettwerk.com   209.17.154.2
Secondary:   ns2.nettwerk.com    209.17.154.1

I assume that I need to log into Network Solutions and change my primary 
and secondary DNS IP's for
nettwerk.com but do I also need to do this for werkshop.com since my 
domain name servers are listed as
ns1.nettwerk.com and ns2.nettwerk.com???  ie) Will it work for me to 
make just the one registrar change
for nettwerk.com and then change ns2.nettwerk.com to be 207.102.64.2 in 
the DNS only ???