Question over the appraisal status change

Question

Dear All,
Our appraisal has ( following the flexible template ) has planning, mid year review and final phases. With in each main status we have sub status configured. Example - In the planning stage ( say in the month of February ) , employee add objectives, change weights etc and send to manager for approval. If manager approves, the document status will be changed from planning  to mid year status and employee's form is changed to the display mode ( so he cannot update objectives / weight etc)
Then again in the mid year  status ( say a few months later - June ist ), the employee needs to review the appraisal, add or update the objectives etc and submit for manager approval.
My issue is -  After the employee's appraisal form is changed to display only from planning to review status - How the employee's appraisal  form can be changed from a read only to change mode in the same status ? As it is necessary for employee to add/ update in the form.
I am seeking the best approaches for the below as I am considering two options ( as mentioned below )
1)   For the  mid year status  , I will configure a sub status ( called start mid year ) and attach a push button. The employee select the push button during the mid year  period ( say June 1st ) and this push button triggers the status change from Mid year to Mid Year / Start Mid year. We also plan to apply a custom implementation for  BADI for column access and badi  (HRHAP00_COL_ACCESS) will decide the access control for columns etc.
2) The other approach I am considering is we are considering a workflow (INFO_APPRAISEE_CHANGE_REVIEW ) to notify th employee 7 days before the mid year review starts. Can this workflow trigger the status change or read the column access from the BADI (HRHAP00_COL_ACCESS) ?
Any other simpler approaches ?
I saw in the Process config ( tabs and process ) that we can define the phase with dates and status / substatus etc. Can this be useful for the above scenario. For eg. On June 1st when the mid year review start, can the status be changed  like from Mid year  to Mid Year / Start Mid year ?
Please let me know . Greatly Appreciated!
Aneez Hameed

Answer 1

Hi Aneez, both options are great,   HRHAP00_COL_ACCESS is configurable at each sub-status, so you have many options.  You can have the manager "approve" at beginning of year, but keep it in "in planning" by having a 3rd sub-status.
You can have the employee or manager have access to the pushbutton so that mid-term can start. 
you can also do a workflow option where it is changed automatically, your option 2.
the final option is the HR adminstrator can change the status, by doing a mass select in phap_admin and then they change to the status to move it to "in review" with all of your mid-term substatuses. 
they key to making this work is the additional config that goes along with HRHAP00_COL_ACCESS.  here you will want to do define a Z table with the following columns:
object id - your template ID
role - which are the same roles values defined at your template - apee for apraisee
template status - integer - represents status ID
template sub-status - ID
column id - FAPP, OBJO, etc..
availability indicator (char) - here you will configure H, X etc... which the badi uses to know how to handle it. 
best regards - michael