Closing, Disabling, and Deleting Activities 
Use these procedures to:
Disable one-time or recurring activities so that they do not appear in the calendar or in reports
Close one-time or recurring activities that are no longer relevant
Delete one-time or recurring activities, even if they are related to service calls, sales opportunities, or activity-related reports
Procedure
Disabling Activities
From the SAP Business One Main Menu, choose
Business Partners 
Activity 
.In the Activity window, display the required activity using standard search functions.
On the General tab, select Inactive.
NoteTo reactivate an activity, deselect Inactive.
End of the note.Choose Update.
Closing Activities
From the SAP Business One Main Menu, choose
Business Partners Activity .Display the required activity using standard search functions.
Select Closed and choose Update.
To confirm, choose Yes in the system message.
CautionClosed activities cannot be reopened or modified.
End of the caution.
Deleting Activities
From the SAP Business One Main Menu, choose
Business Partners Activity .Display the required activity using standard search functions.
From the menu bar choose
Data Remove .To confirm, choose Yes in the system message.
Note
When removing recurring activities, the system asks you Would you like to remove only this event, only unchanged events of this recurrence or all events of this recurrence? Select the radio button Only this event, Remove only unchanged events, or Remove all events and choose OK.