one hba is in standby mode

Hi Everyone,

     We have two redundant fabrics.Last week we replaced core switch from one fabric due to hardware failure.We have multiple servers connected to this fabric.

we were able to recover the second path on all AIX,solaris and windows servers.We also have ESX VMware servers connected to this fabric.We have two hba's in each ESX server and zonned to two redundant fabrics.Now my question is the hba's which are zonned to the fabric where the core switch has been replaced are in standby mode.How to bring back the hba's from standby mode to active mode.