How to change hardware dns?Please lead us!

Dear  Sir/Madam
IN  Ripe NCC
DNS  WG Staff

Hello,I hope you have fine time,

We are  one  of  your LIR and  have two DNS  server which work  as
primary  &  secondary.because of  old  hardware version of this  server
we deside to  change  primary  server  to  new system  without  losing
zonefiles  which  registred  at  dns  manager  and  disconnecting  of
internet  connection of  our  customer.we  know  that  one way is create
 primary  as a master  and  other  system  as  slave and  forward  files
to new system then  converting  new system  to  primary whith the same
ip.but  we  intrest  that  is there   new and  easy way  to
transferring  zone files from old  system to  new  system?and if we have
only  master & slave configuration to rech the aim do you please  lead
us  with step  by  step  configutation to success prossessing.We deside
change only  system from nt 4. to new  system with  same IP  address.

Please  advise us
Thanks a lot
The Best regards.