Anyone negotiated salary few days before joining?

Hi, I have an offer from Company A and my joining date is in next 2 weeks. But just last friday i got another offer from Company B with much higher salary than A.

But I have interest to work on Company A. Do you think I could negotiate with Company A so close to the joining? Has anyone done it before and what was your result? I'm worried if they may rescind the offer if I asked. Appreciate if anyone could shed some light on how to approach this.

Thanks.