Hi @ShahidaValiSyed04 

Can you try like below please:

And it will rename the field.

hi @ShahidaValiSyed04 ,

Are you trying to change customized field or Default Acumatica field? if default Acumatica what is the field on screen?

Alternate way you can write the logic on the extension graph with two approaches,

1)Cached attached

Sample Code:
 �PXMergeAttributes(Method = MergeMethod.Append)]
 �PXCustomizeBaseAttribute(typeof(PXUIFieldAttribute), nameof(PXUIFieldAttribute.DisplayName), "Customer Order Nbr.")]
 protected virtual void SOOrder_CustomerOrderNbr_CacheAttached(PXCache sender) { }


2)RowSelected event 

Sample Code:
PXUIFieldAttribute.SetDisplayName<ABCOrder.status>(Base.ProdOperRecords.Cache,  "QCO Status");
PXUIFieldAttribute.SetDisplayName<AMProdItem.statusID>(Base.ProdOperRecords.Cache, "Order Status");

Hi @ShahidaValiSyed04  According to me code level changes are NOT required. 

You can use workflow and with a few clicks you can change the field name and very simple.

Please find the below steps to rename the field.

• In the Customization Projects, select the Screen by clicking the “Customize Existing Screen”
• Left menu, expand the screen, click on the Fields and choose the field which you wanted to rename
• Change the display name
• Do Publish the package

Screenshots for your reference.

Thank you guys