Hi Amala,
Maybe other community members have some ideas on this. The only thing that came up on my end is to do an UpdateObject on the bmhier table and set the delete_flag attribute to 1
Checkout the grloader approach that was discussed here:
Remove CI Relationships with GRLoader
A sample Create Relation is discussed here:
In a similar way you could use PAM to call updateObject SOAP call in SDM to set the bmheir:xxxx with delete_flag=1
PAM::. UpdateObject - Process Example
Hope this helps
_R