If you know the query is still the ActiveDatasheet, requery that:
Screen.ActiveDatasheet.Requery
If you don't know that (you could check Screen.ActiveDatasheet.Name), you can open it again (which may or may not requery if the query is already open -- I would expect it not to, but I could be wrong), and then it will be the ActiveDatasheet and you can requery that.
Or, you could do:
DoCmd.SelectObject acQuery, "NameOfYourQuery"
Screen.ActiveDatasheet.Requery
Surely one or more of these methods will work.
But let me point out that it's not a good idea to use tables and queries as user interface objects. You should instead make forms for allow users to interact with the data displayed in them because that gives you far more control over them.
(one thing that many people do not know is that a datasheet is a form object, so the properties and methods of Screen.ActiveDatasheet are the same as those of any form, which means you can actually assign values to events on the Screen.ActiveDatasheet object and have them fire; but I wouldn't recommend this as the easiest route to building a UI...)