how to put modifiedby User column values from Multiple rows for the same Id in comman separated in SSRS Report

Hi Team,

How to put Modifiedby User columns values from multiple rows for the sameid in comma separated in SSRS Report.

For example in the below table we have requestid 501 had been modified by many users... We want to generate report like below in SSRS

RequestID : 501

Request Name : OS Installation

Initial Request By :User1

RequestModifiedBy : User2,User3,User4

ProjectID:1

how to do this...Please help... Like RequestModifiedBy we have many columns...

CREATE TABLE [dbo].[RequestDetail](
[ID] [int] IDENTITY(1,1) NOT NULL,
[RequestID] [int] NOT NULL,
[RequestName] [varchar](50) NOT NULL,
[RequestedBy] [varchar](50) NOT NULL,
[RequestModifiedBy] [varchar](50) NOT NULL,
[ProjectId] [int] NOT NULL,
)

GO

SET IDENTITY_INSERT [dbo].[RequestDetail] ON

GO
INSERT [dbo].[RequestDetail] ([ID], [RequestID], [RequestName], [RequestedBy], [RequestModifiedBy], [ProjectId]) VALUES (1, 501, N'OS Installation', N'User1', N'User2', 1)
GO
INSERT [dbo].[RequestDetail] ([ID], [RequestID], [RequestName], [RequestedBy], [RequestModifiedBy], [ProjectId]) VALUES (2, 501, N'OS Installation', N'User1', N'User3', 1)
GO
INSERT [dbo].[RequestDetail] ([ID], [RequestID], [RequestName], [RequestedBy], [RequestModifiedBy], [ProjectId]) VALUES (3, 501, N'OS Installation', N'User1', N'User4', 1)
GO
INSERT [dbo].[RequestDetail] ([ID], [RequestID], [RequestName], [RequestedBy], [RequestModifiedBy], [ProjectId]) VALUES (4, 502, N'Driver Installation', N'User5', N'User74', 3)
GO
INSERT [dbo].[RequestDetail] ([ID], [RequestID], [RequestName], [RequestedBy], [RequestModifiedBy], [ProjectId]) VALUES (5, 502, N'Driver Installation', N'User5', N'User81', 3)
GO
INSERT [dbo].[RequestDetail] ([ID], [RequestID], [RequestName], [RequestedBy], [RequestModifiedBy], [ProjectId]) VALUES (6, 502, N'Driver Installation', N'User5', N'User90', 3)
GO
SET IDENTITY_INSERT [dbo].[RequestDetail] OFF
GO