Yes and no
In some cases the website will allow you to hold an award itinerary for free if you are physically in Chile, Peru, Argentina, Colombia and Ecuador (or if you use those local sites) if you choose an offline form of payment (which you can later change if you go to My Trips and choose to pay for the reservation with a different form of payment -say, credit card-).
However, this doesn't allow the reservation to be held indefinitely. They will only hold if until the ticketing time limit (which is usually between 23:59 local time on the same day you make the reservation and 24 hours counted from the time you create the reservation). Upon reaching that ticketing time limit, a revenue integrity automated process will cancel the itinerary.
While the above is possible, I don't think it'll give you anywhere near enough time for the SPG transfer to occur, so in this case I'd say you are out of luck (LATAM doesn't offer, unlike other airlines, to hold reservations for longer if you are willing to pony up a small fee)