I think you are asking the difference between これ and この / あれ and あの / それ and その, and wether they are interchangeable or not.
First of all, they aren't interchangeable.
When "this" is not connected to a noun --> これ
This of "this + noun" --> この
This is a book. = これはほんです。
This book is mine. = このほんはわたしの(もの)です。
The same happens for "that", and about それ and その, それ is "it" and その is "the" and sometimes "that + noun" can be translated into その depending on the situation / sentence.
If I understood your question, please let me know. I hope this was helpful.