Sentence case without altering the proper nouns

Question

Sir, I need to convert multiple sentences in a cell into sentence case. Kutools is able to do that, but one problem: if I had intentionally capitalized the first letter of a word (for example, a proper noun such as Delhi, Yudhistra, Arjuna, etc), Kutools converts its Upper case into lower case. Delhi becomes delhi, Arjuna becomes arjuna, etc.  This is not right. How to resolve this? Thank you.