what functional privileges/roles are needed to edit service dates and user person types,asg status

Summary:

We have a requirement to give additional privileges to a custom role that is supposed to administer a special subset of people.

I've tried add some security roles to this custom role but can't seem to give access to the following two functions.

Can you please help me identify which functional privileges / Roles (in role hierarchy) are needed to allow the following ?

1: Edit Service dates (Legal employer start date) from person management --> work relationship --> Action

  task. This is because sometimes people enter the wrong hire date and this role needs access to 

  change these dates. One way to do that is to change the legal employer start date.