Testing - Planning tests with configurations and assign multiple testers

Hi all,

Is it possible to change configurations on test cases directly from team Web Access ? I haven't found anything about it. Only from MTM

Is it possible to "undo" a tester on a test case after assigning multiple testers (3 testers on 15 test cases and one of the 3 testers can't run all of the 15 test cases)

Thanks for your help

M.