How fast a H1-b transfer from a new joined company to another be done

Want to know how long i have to stay in a newly joined company to do another H1 transfer.

One week back i was working with company A and now, this week i moved to Company B.

Now i have got a better offer from another company C, so can i do my H1 transfer to C immediately or should i wait for some time.

What is the procedure in this situation. Please help