I'm new to Microsoft Dynamics CRM development. I need to change attribute in campaign entity when current date time will equal "actualstart" attribute. Is it possible?
You should be able to accomplish this via a Workflow. Create a Workflow against the Campaign entity and add a Wait Condition where Process - Timeout - Equals - Actual Start. Then embed whatever logic you want to run at that time within the Wait Condition. Activate the Workflow, run it on-demand against the desired Campaign and it should kick off a System Job that will "Wait" until the Actual Start time and execute the logic you specified.