You're correct, Barb - merging is a different issue. You can propose a merge between any two profiles, regardless of their privacy level and regardless of whether or not you are on the trusted list.
If you are a manager of both profiles then the merge will happen immediately because WikiTree will assume that you approve it.
If you are manager of one of the profiles then that will show your approval, again because WikiTree will assume that you approve it. The other profile manager will have an opportunity to review your merge proposal and either approve it (in which case it will happen immediately, since the first manager (you) have already approved it The manager can also reject the merge. If the manager does neither of those things in 30 days then the merge will automatically receive default approval, but it will not be automatically completed. Any WikiTree member can approve the merge after that to make it happen.
If you are not the manager of either profile then it works pretty much the same, except that in this case both managers have the same 30 day opportunity to approve or reject the merge and if both approve it during that time then it will automatically happen immediately.