Hi Ashok,
yes its possible to change the length/ Title of the Field added through AET.
1- Identify Extension ID of the AET field (Transaction AXTSHOW) .
2- Adapt Metadata: Change in Table AXT_EXT_PART_DTL (OBJ_PARAMETER LENGTH, set OBJ_PARAMVALUE to the desired length).
Include the entry in a transport order (Mandant intependent, Workbench order).
3- Adapt Metadata: Change in Table AXT_CAT_OBJ_DTL (OBJ_PARAMETER LENG, set OBJ_PARAMVALUE to the desired length).
Include the entry in a transport order (Mandant intependent, Workbench order).
4- Include in a transport order the Extension ID (Workbench order)
5- Run AXT_EXT_ANALYZE -> No inconsistencies found
6- Regenerate the extension (Transaction AXTSHOW)
7- Set the final width in the domain (SE11) (Workbench order).
Pls let me know in case of any issues...