REFERENCE: http://technet.microsoft.com/en-us/library/jj945659.aspx
Use the SEFAUtil.exe tool:
SEFAUtil.exe /help for a list of uses
PS C:\Program Files\Microsoft Lync Server 2010\ResKit> .\SEFAUtil.exe
SEFAUtil.exe [/server:<Lync Server FQDN>] <SIP URI of user>
SEFAUtil.exe [/adddelegate:<SIP URI of delegate>] /simulringdelegates [/server:<Lync Server FQDN>] <SIP URI of user>
SEFAUtil.exe [/adddelegate:<SIP URI of delegate>] /fwdtodelegates [/server:<Lync Server FQDN>] <SIP URI of user>
SEFAUtil.exe [/adddelegate:<SIP URI of delegate>] /delayringdelegates:<Delay in Seconds> [/server:<Lync Server FQDN>] <SIP URI of user>
SEFAUtil.exe [/removedelegate:<SIP URI of Delegate>] [/server:<Lync Server FQDN>]<SIP URI of user>
SEFAUtil.exe [/setfwddestination:<SIP URI of destination>] /enablefwdnoanswer [/callanswerwaittime:<Call answer time inseconds>] [/server:<Lync Server FQDN>] <SIP URI of user>
SEFAUtil.exe [/setfwddestination:<SIP URI of destination>] /enablefwdimmediate [/server:<Lync Server FQDN>] <SIP URI ofuser>
SEFAUtil.exe [/disablefwdimmediate | /disablefwdnoanswer] [/server:<Lync Server FQDN>] <SIP URI of user>
/server: Lync Server FQDN, required if auto-discovery is not enabled
/adddelegate: add delegate on-behalf of the user
/removedelegate: removes delegate on behalf of the user
/simulringdelegates: Sets user's call handling rules to ring delegates endpoints simultaneously
/delayringdelegates: Sets number of seconds Boss' endpoints ring before ringing delegates
/fwdtodelegates: Sets user's call handling rules to forward calls to delegates
/setfwddestination: Sets the user's forward immediate or forward-no-answer destination
/enablefwdimmediate: Sets user's call handling rules to immediately forward all calls to Fwd Destination
/enablefwdnoanswer: Sets user's call handling rules to forward unanswered calls to Fwd destination
/callanswerwaittime: Sets the number of seconds to wait for user to pick up the call
/disablefwdimmediate: Disables forward immediate
/disablefwdnoanswer: Disables forward-no-answer
No switches: Displays the call forwarding settings of the user.