You can edit or delete any activity, except email interactions, directly through the Activity timeline in any profile.
Select any profile and click on the Activity timeline, as shown below.
To edit an existing interaction simply click the pen icon on the right side next to any interaction to update timestamps, submission questions, etc.
To delete an existing interaction simply click the trash icon on the right side next to the interaction. Please note this is action is permanent and deleted interactions will no longer be available once deleted.