Go to the relevant client’s account, and under ‘Account actions’ select ‘Withdraw’. You can then select whether you wish this to be a single or regular withdrawal, the amount (and payment date and method if it’s a regular), and you can select whether you’d like to instruct an auto-disinvestment.
You can also instruct a withdrawal via the Sell process and this is useful if there is insufficient cash on account, but you do not wish to trigger an auto-disinvestment – you'd prefer to sell specific funds and/or units. In this case, you would go to the client account and then select ‘Sell’ from the Actions menu. You then input the units or amounts you wish to disinvest from each asset, and you choose ‘assign sale proceeds’ as ‘withdraw’. You then select review and submit the instruction, and this triggers the sells and the subsequent withdrawal.