Sytax for EDIT Pushbutton in Module Pool

Hi Experts,

I am new to ABAP.

I have a Ztable and with F4 help and pushbutton syntax I am pulling the data from Ztable on my screen (Created by Screen painter) in MPP:

I have 4 pushbuttons: Get_Data, Edit, Delete and Save.

If I want to edit a pulled data from Ztable, then what sud be the syntax for Edit pushbutton in sy-ucomm.

My code on Mod Poll (Main progg) Screen in:

module USER_COMMAND_9000 input.

Case sy-ucomm.

****************************************************************************

*To Populate Data into Mitarbeiter through Pushbuttons

****************************************************************************

When 'OK_GETM'.

IF ZLT_MITA-M1 is NOT INITIAL.

SELECT SINGLE *

FROM ZLT_MITA

Where M1 = ZLT_MITA-M1.

ENDIF.

When 'OK_DELETEM'.

IF ZLT_MITA-M1 is NOT INITIAL.

DELETE

FROM ZLT_MITA

Where M1 = ZLT_MITA-M1.

IF sy-subrc = 0.

MESSAGE S000(8i) With 'Data deleted'.

ENDIF.

ENDIF.

When 'OK_EDITM'.

Update ZLT_MITA. ------------------------------> This doesn#t Edits the existing data in Ztable

IF sy-subrc = 0.

MESSAGE s000(8i) With 'Data Updated'.

ENDIF.

When 'OK_SAVEM'.

Modify ZLT_MITA.

IF sy-subrc = 0.

MESSAGE s000(8i) With 'Data Saved'.

ENDIF.

Can nay one please help me out.

Regards

Deepika