For the Mass update of global subscription status do the following
Go to Lists > Mass Update > Mass Updates.
Expand General Updates, then click Company, Customer, Partner, or Vendor.
Set criteria for the users we want to update.
On the Mass Update Fields subtab, check the Global Subscription Status box.
Select the status which want to set: Soft Opt-In or Soft Opt-Out
All records that match the criteria you have set and that are permitted to be changed through mass updates will be set to the selected status.
Click Save.