"I haven't, no. Give me a minute," Regulus said. "I'll be back in a moment."
He turned and headed off to his bedroom; he didn't have suitable clothes in his wardrobe, but he could Transfigure some - he hoped. He'd had a couple of magical mishaps lately, and he meant to have his wand checked at Ollivander's soon to make certain there was nothing wrong with it. In the meantime, he didn't want to do any spell work in front of an audience in case his wand misbehaved again.
Fortunately, he was able to transform his robes without any problems, and he chose to dress far more casually than he usually did, turning his robes into jeans and a thick wool sweater. He Transfigured a cloak into a warm jacket and donned a pair of boots, and then he rejoined Sirius.