That's what Prigozhin said he would do.
Today he says Shoigu will give him all the ammunition he needs, and Russian forces will be sent to protect his flanks, and the retreat has been cancelled.
Btw, all of this is just theater for the Russian audience and has no bearing on the course of the war. Bakhmut has served it's purpose, and however many additional tons of munitions they expend on the last remaining blocks, it won't be worth it. Every shell used in Bakhmut is one that's unavailable when the Ukrainian counteroffensive gets underway.