When the dissolve delay timer for a neuron reaches zero, it is dissolved and you can disburse the neuron’s stake and transfer its locked ICP utility token balance to the ledger account you specify.
To disburse a neuron and return its ICP utility tokens:
Step 1: On the NNS dapp, go to the Neuron Staking tab and then the table Staked ICP. Then click on an dissolved neuron that has reach the ended of its dissolve delay period (indicated by 'Unlocked').
Step 2: Click Disburse.