Hi Dina--
To do this for all instances in the document, you will probably need to write some ACL script code. Here is some code you can use as an example:
oid_find_children(oid_root(),$oids,"indexterm");
for ($o in $oids) {
oid_delete($oids[$o]);
}
This will eliminate all the instances of the element <indexterm>. Just replace that name in the first line with the name of the element you want to remove.
Put this code into file with the extension *.acl, for example "delete_indexterms.acl". You can put it in your scripts folder in the custom folder, and then run the code on a document by loading the document and typing "source delete_indexterms.acl" on the Arbortext command line.
--Clay