Changing from Individual trustee to corp trustee for SMSF Holding trust

My SMSF is buying a property (yippeeee)

I was poorly advised in the early part of my SMSF journey and my SMSF was established with an individual trustee for my Holding Trust (ie/ me as an individual).

Last week I went to a SMSF Trustee education seminar and the strong recommendation was to have a corporate trustee for the Holding Trust.
(The Holding Trust will be borrowing money under an installment warrant so the SMSF can complete the purchase.)

So – how do change the individual trustee to a corporate trustee???

I need to do this fairly quickly, as I sort-of bought the property at auction on Saturday.
Sort-of,as it passed in, and I negotiated and agreed to meet the vendors reserve, but I took a standard sale contract not an auction contract. So when I go to sign the docs on Monday pm and put down the 0.25 per cent deposit, do I sign as the individual Holding Trust trustee or do I put up the deposit, dont sign anything, and ask for a few days to get the corporate trustee in place? or can I change trustees after I pay the deposit, but before we fully exchange???

I dont want to shilly-shally too much as the reason I got it at a good price was that others could not get finance in time, so if the vendor goes back to the market she will get quite a bit more than under auction conditions.

All comments appreciated. I need to act by 4pm Aug 2.