To make sure you don't forget to release a lock you don't need any more, locked objects are shown in the Team development Locks tab.
To release a lock manually, select the objects in your working copy KB for which you want to release the lock, then select the Team Development contextual menu Release Lock option; GeneXus will contact the GXserver repository and release the locks on the selected objects.
Check the status on the Team Development output window, you should get a detail message similar to the following:
========== Release Lock started ==========
Contacting GeneXus Server at 'http://...'... done!
Exporting Transaction 'Invoice'...
Export File Created At: 'C:\Users\genexus\AppData\Local\Temp\tmpBD49.xpz'
GeneXus Server: Processing file...
GeneXus Server: Checking Import References...... Finished
GeneXus Server: Reading import file objects...... Finished
Released Lock in Invoice
Release Lock Success