[CentOS] Subnet expansion

Hi all,
Can pls share your experience on this?

Currently I have this network:
10.1.16.0/22.
10.1.16.0-10.16.17.254 are DHCP managed
10.1.18.0-10.1.19.254 are statically assigned

If I need to expand it to:
10.1.16.0/20

1. What is the best way to do it with minimal network disruption?
2. If I keep some machine with 22 subnet mask, will it still be able
to talk to the other machines in it's range?


Thank you.
Fajar.