Unshare a shared workbook

I’ve created a master file for multi users where I’ve done a lot of conditional formatting, drop down menues and locked sensible cells containing formulas. The moment I thought I was done test driving it, I said to myself I should make it shared. Now, after further testing I realized I needed to unlock some cells to do some tweaking, however I don’t seem tofind an option or any kind of indication as to how to unshare the workbook so I could unlock the cells. Anybody has an idea I’d mostly apreciate that?