Had a quick look at the dashboard and couldn't find an obvious answer...

Here's my scenario(in July)

I'm flying QR to Stockholm (arriving: 19:45)

I need to get straight back to LHR - there is avios availability for the 21.15 ARN-LHR.

This gives a 90 minute layover.

If my QR flight is delayed - how late on can I change my avios booking to the following morning(assuming there's availability)

Something in the back of my mind suggests t-24 hours. But I'd be delighted to be wrong.

Thanks