Thanks for your response, Sparrow_kop. I will note that I am interested in the drug target data from the DrugBank database, and as far as I've seen, the only ID provided for each target is in the XML path <targets> --> <target> --> <id>, which only provides the BE-form identifier, and no UniProt ID... So, I remain with the problem that I have only the BE-form IDs for my targets, and ultimately want to convert to Entrez format...
Another interesting observation is that, despite the extensive list of descriptions provided by DrugBank for the source of each field ( https://www.drugbank.ca/documentation#drug-cards ), I do not see the Biological Entity (BE) format mentioned anywhere... This documentation lists UniProt, GenBank, and PDB ID formats as being available for Target info, but in reality, after I have extracted the <targets> --> <target> --> <id> content for each target, this info seems only to ever be in BE format.