just want to add to sid reply...
1. why allow employees to alter bank details? it can cause you headache if you implement payroll.
2. managers do not need to see bank details of employees,.. as sid says,.. usually on behalf of functions are leave request time entry address update etc,...
3. you really need to look at point 1,.. it0009 is closely tied to time and pay,.. if you do allow employees to change bank details you may want to think of putting in extra controls,.. like allow change of 'other' banks only and not the main bank... or,.. assuming you have payroll,.. some kind of control on the portal (this will be messy) to say an employee cannot change bank details x no of days prior to payrun and y no of days after,.. I wouldnt really go down this path personally.
4. lastly,.. control og it0009 through auths is a simple and effective fix but in real life I have seen very few customers open to that solution...
cheers