The girl band has temporarily relocated to California in a bid to launch itself in the U.S., and the All Fired Up hitmakers are due to hit the stage at the famous The Roxy Theatre on Tuesday (30Oct12).
But Sandford will not be part of the line-up after flying back to the U.K. to mourn the loss of her elderly relative.
Breaking the news to fans on Twitter.com on Thursday (25Oct12), she writes, "Hey guys I've had some really sad news. My grandad has passed away. im going to go back to the Uk for the funeral and to be with my family. Im gutted to be missing the Roxy show, I was really looking forward to it. But the show must go on. Sorry guys, hope you understand."