We have tons of new agents (
). Nodes are also exist, polled by ICMP. These hosts are not ours, we have no credentials.
So in case there are few of them, I can check them one-by-one and press "Manage as node" button:

^ Manage Agents page
And if I change the polling method from ICMP to Agent one at a time, no credentials are asked, it just say "Agent software is installed" and everything is fine:

But. You can't just check several nodes and press "Manage as node", because button is not active anymore (Dunno why, bad UI problems):

^ Manage Agents page
Okay, let's try to change polling method from Manage Nodes page?

^ Manage Nodes page
Now it asks for credentials (Why? Agents are already deployed. Very unexpected behaviour)

How to change polling method for nodes simultaneously without entering credentials?
Adding moar than 20 nodes (we have 300+ actually) one-by-one is a hell and just wasting of time.