what failover mode are you using right now ..also are you on vSphere ?  Take a look at this command, this will trespass all LUNs whos default owner is SPA. Then you need to run the same thing agains SPB  navicli -h trespass mine   be carefull as these will trespass ALL LUNs on the array, if you want to trespass individual LUNs  navicli -h trespass LUN 28 
Hi!  Me again Margaret.   I have been playing and just can't seem to find the answer to this particular issue.  I have over 300LUNs across 4 SANs that are all ESX.  I am in the process of getting my happy hands of PowerPath/VE but it will take a while.  In the mean time I am looking for a quick way to tresspass all the tresspassed LUNs on an array back?  Anyone have a clue?  CLI script perhaps?  TJ 
Easy Tresspass LUNs