The assignee can be updated for a set of bugs simultaneously using group actions. In any view of the bugs module, click the Group Actions button near the top of the module and select Update Assignee to open the pop-up wizard.
The pop-up will list the available bugs. Select the bugs by clicking on each, or click the Select All button to select all the listed bugs. To remove a bug from the selected column, click on the corresponding . When ready, click the Next button. In the next screen, select the intended assignee from the list of available users. Click Submit to continue with the assignee change.
Note that this group action feature is available to users that have access to the bugs module. The list of bugs provided under a group action will be those for which the user has access. Depending on the settings of the users project permissions, they may be able to see all project members or a subset.