dhtmlx scheduler onBeforeEventChanged

When the user make drag and drop I use

scheduler.attachEvent("onBeforeEventChanged

for check the errors and return in case of errors false.
When onBeforeEventChanged return false the event turn in the original position.
This a problem because I have to call many api rest to check if there are errors and after repeat the execution of the checks functions when update and save.
Is possibile to use

onEventChanged and in case of error the event turn in the original position

Because in this way I have to make a double controll, where in the first case I don’t work with entity but params