When the maturity in your neuron multiplied by the number of staked ICP is greater than 1 ICP, the “Spawn” button will become active and you can spawn a new neuron. Spawning a neuron means withdrawing the maturity (or ICP rewards) from your staked neuron in the form of a new staked neuron. This new neuron with freshly minted ICP has a dissolve delay of 7 days and is locked. If you want to remove the ICP reward from this new neuron, then you must unlock the neuron and wait 7 days.
The ICP Guide
The definitive guide to the Internet Computer Protocol (ICP)
