how to add witness server without breaking mirroring in sql server ?

Hi All,

I have get different request from my client side. Actually few months back we have configured Mirroring (2TB database) without witness server (without automatic failover ) .

Now I have get new request like without breaking the mirroring add the witness server to mirroring.

Please guide me, how to add witness server without breaking mirroring in sql server 2008.

Thanks in advance.

RAM