On the Web Agent Side , the system HostID is used during the encryption of the shared secret in the SmHost.conf file.
So if change of IP results in the change of HostID , then it will make the current shared secret invalid, requiring you to re-register the trusted host.
However, if the change of IP doesn't result in the change of HostID, then there won't be any impact with regards to the shared secret.
Now, different OS has different approach on how they compute system HostID. Some use IP address during this calculation while others don't.
Please refer to respective vendor documentation to confirm if the IP change will have any impact with the system HostID.
For e.g for Linux please refer :
On the Policy server Side however,HOSTID is not used during the encryption of EnryptionKey.txt file.
So change of IP address/Mac address etc. have no impact on Policy server side.