some times but YMMV
Thanks.
UPDATE Backstory: my wife needed a flight to Israel last minute and transferred SPG points to Delta (please, spare the comments on Skypesos being worthless and how wasteful it is to transfer SPG points to Delta. When you're in a pinch and you need the flight and SPG is the currency that will take you there, Skypesos fit the bill when others couldn't in this situation). After she made the transfer, she got the confirmation that it could take "up to four weeks" to transfer the points. It's Sunday night, and she needs to fly out next Monday (7 days). Needless to say she was upset, and rather anxious.
The possibilities we considered were: (1) waiting to see if the points would transfer within two days, as reported by numerous users; (2) call SPG and request the transfer be expedited; (3) call SPG and request that the transfer be cancelled, since the points didn't yet post to Delta.
A wrinkle thrown into the mix: the Delta flight was 145K points, and she needed to transfer 120K SPG points to get it. Since you can only transfer 79,999 SPG points in any 24-hour period, she would have to make 2 transfers 24 hours apart at 60K a piece. She was nervous that even if the first transfer would post in 2 days, the second transfer might not post in 2 days, or the award flight would no longer be available by the time the points transferred in 3+ days.
We decided to call SPG. My wife spoke with a very helpful agent who explained that, unfortunately, the transfer could not be expedited. While transfers normally cannot be canceled, she would be able to cancel my wife's transfer because the transfer was made recently (only a few hours prior).
The points were back in her SPG account 2 mins after she hung up with the SPG agent.
My wife ended up booking through SPGflights.com, which again, I realize is not a good exchange rate for the SPG points, but when the flight is necessary and it gets her to Israel on time, and it makes her happy, it's worth every penny in my book.
Lesson learned: When in a pinch, it's always worth calling the agent to ask.