To delete the contact entry:
Go into the candidate record and the Career tab.
Amend the career entry which is making them a current contact.
Change the Status field of the career entry to Previous and set the Contact type to none.
This would stop them from being a contact leaving just the candidate record in place.
To delete the candidate part of the record:
Go into the candidate record and then to the Types tab.
Depending on whether they are a perm or temp candidate, select the relevant tab.
Then press F8 on your keyboard. (i.e. Click the perm tab then press F8).
⚠️ Important: A pop out will appear asking if you want to delete this type. If it does not say this, do not go ahead with this as it could remove the whole record, especially if it says 'Do you want to delete the entire record'.