withdrawal of provisional

I agree with Steven - this is an unusual question. Are you concerned that the provisional application may eventually be published containing disclosure that was omitted from the complete application which you would like kept confidential? If so, it is not necessary to withdraw the provisional application - provisional applications do not get published.

Your question is perplexing - 1) why would you want to withdraw the provisional - as opposed to simply let it expire after the one-year time period from the date of filing of the application? 2) Why would you publish the application after having filed the provisional application? Publication of your application destroys your foreign patent rights and initiates a one year grace period in the US to file your non-provisional application. That being said, I do not believe that you can actually withdraw a provisional as I have never done it myself - I guess that it is possible to file an express abandonment of the provisional application just like you can do with a non-provisional.