@bindukumari1990 You would need to go with Data repair API to delete a specific dimension item,
The Data Repair API provides you with a way to delete or edit Adobe Analytics data. Repair requests are made by submitting a job definition to the Data Repair API, which includes the report suite, date range, variables and actions to be applied to the data.
Here is the documentation on the same
Note: This is a paid service, you would need to connect with your account manager to avail this feature