Currently I have a 10.10.10.0/24 network and am running out of IP Addresses. I'm not sure if I change to /22 mask, if I will still be able to communicate with some of the other facilities where we use 10.10.30/24, 10.10.40/24, etc. Any advice appreciated, thanks.
If you change to /22 the network would be 10.10.8.0 to 10.10.11.255, which doesn't overlap with your other addresses.
Whether your routing or filtering will let those source addresses out to your other branches, or whether packets will come back, is another question. But certainly it's possible to reconfigure your routing/access control to permit your /22 without clashing.
NB: The most complete question on addressing and masking is How do you calculate the prefix, network, subnet, and host numbers? which is the best place to look for understanding these things in detail.
Just to adjust jonathanjo's good response, changing the mask to /22, the network would be from 10.10.8.0 to 10.10.11.255. You can use ipcalc in Linux to check:
$ ipcalc 10.10.10.0/22
Address: 10.10.10.0 00001010.00001010.000010 10.00000000
Netmask: 255.255.252.0 = 22 11111111.11111111.111111 00.00000000
Wildcard: 0.0.3.255 00000000.00000000.000000 11.11111111
Network: 10.10.8.0/22 00001010.00001010.000010 00.00000000
HostMin: 10.10.8.1 00001010.00001010.000010 00.00000001
HostMax: 10.10.11.254 00001010.00001010.000010 11.11111110
Broadcast: 10.10.11.255 00001010.00001010.000010 11.11111111
Hosts / Net: 1022 Class A, Private Internet