you use the info from the holding statement you received when...

you use the info from the holding statement you received when they notified you they were going back onto the registry

ie 1500 off
75 on

there's a SRN somewhere on the sheet

just in your online broking account look for a 'convert holdings' option in westpac it is under 'my portfolio'

then put in the details exactly as they read
name
address
asx code
srn
number of shares

it should show up after about a day
if this option isn't available you'll have to contact your broker for a transfer form