Which indexes and tables needs to rebuild after workflow purge

Hi All

We always purge old workflow data by using seeded conc req "Purge obsolote Workflow runtime data" and via Seeded API WF_ITEMS.purge etc.

But, after that which workflow tables and indexes  needs to be rebuild so that we can reset the High water mark and save the space?

I think we can only rebuild only certain indexes on  following tables. But how to rebuid those tables? Is there any standard methods?

'WF_ITEMS',
'WF_ITEM_ACTIVITY_STATUSES',
'WF_ITEM_TYPES',
'WF_ITEM_ACTIVITY_STATUSES_H'

Regards

Nikhil Wani