Don't assign the VLAN in the system programming.

Get the IT Dept to make the change on the switch ports.

The same applies with the ITP phones.
There is a firmware bug with the ITP handsets where they won't obtain a DHCP when you set them up with VLAN tagging.
I didn't discover this bug until the ITP handsets were EOL so Samsung wouldn't fix it.
The SMT phones don't have this issue.

You will need to change both the MP40 and OAS card IP Address
Possibly the SVMi20i IP address if you have that as well as the system talks to it via the LAN.