Left open by his words. The standard process is in Riddick's Senate Procedure - pp 1129-1131. "Parliamentary fun."
I think the timing of taking it up is indefinite, meaning the Senate can reconsider the vote when it wants to. Frist may conclude the Brown and Pryor matters first (they are not contentious, given the MOU) before moving to take up the Motion ot Reconsider the Cloture vote relating to Bolton. (phew - that was a mouthful)
Riddick's - Pages 1124-1149 - Reconsideration <- Link to 1.6 Mb PDF File
Sure, but he may also elect to deal with Bolton first so as not to give the Dems the ability to say "See, look how nice we were, confirming two ultra right-wing, extremist, cross-burning judges!"