Change the description of standard element

Hi,

I need to change the description of (VBAP-MVGR1 'Material Group 1') field, which system is using in Transaction Code VA01,VA02 & VA03 (Additional data as per item level). Pls suggest me how to change it's description. Clients wants to add his own description here.

Should i change the description of data element directly with access key?

pls suggest.

Thanks in advance.

Pradeep