IF a candidate becomes a validator they cannot withdraw immediately but have to initiate a withdrawal. They can claim this withdrawal until 2 epochs later.
For eg. If a candidate stakes his ETLs to start a pool in Epoch 15 they will be able to withdraw their stake immediately in the same Epoch since they will not be selected as a validator and their pool will not be selected until the end of this epoch 15. In this case their unstaked ETLs will reflect back in their wallet immediately after.
But if they do not withdraw their stake and the pool is selected for the next Epoch (which is true for most Epochs currently) then they cannot withdraw immediately in the same Epoch i.e for the purpose of this eg. Epoch 16. They can initiate a withdrawal in Epoch 16 but they will not be able to claim or view it immediately in their wallet. The pool will become inactive and will not be selected for the next epoch. The ETLs, though, will still be visible in the pool.
In Epoch 17, the participant will no longer be a validator or candidate and though their withdrawal request will be active and in process they cannot claim the withdrawal yet. In this Epoch the ETLs will neither be visible in the pool nor in the wallet.
In Epoch 18 the user will be able claim his withdrawal and the ETLs will reflect in his wallet immediately.
A participant cannot withdraw at the end of an epoch during which the validator selection process is undertaken. As mentioned above the time span for this process is 14400 blocks which is 12 hours for 3 seconds block. This time-span could vary if the average block time is different.
Please also note once a participant unstakes all their ETLs from a pool they cannot use the same account to create a new pool.
To create a new pool the participant will have to create a new account on MetaMask, providing the wallet address from that account for staking.
To start a new pool on Vultr or Digital Ocean, the validator will have to undertake the same process as on AWS.