What is a Particle network?
If you mean an existing mesh, then yes, you can via CLI (see particle mesh --help
).
But, while the idea was that any gateway capable device which joins a micro network that doesn't currently have a gateway assigned to it would be promoted to become the new gateway automatically. As it turns out that feature doesn't (currently) work as intended.
See this thread
That limit only means 10 concurrent, current networks. Once you remove all devices from an existing network the network will disappear and your 10-network-quota will get that one now free instance back.