A demonstrative pronoun demonstrates where something is. That is used for a singular item which is far away. This is used for a singular item which is close. Those is used for plural items which are far away. These are used for plural items which are close. In this sentence "that" is being used as a demonstrative pronoun. It can stand alone since it is used as the subject of the verb "was".
The sentence "John wants that record" uses "that" as a demonstrative adjective. It comes directly before the noun "record" and demonstrates which record it is.
Demonstrative pronouns are substitutes of nouns or noun phrases that point or indicate specific things, elements, people or animals that are near or far in distance or time. They can be singular or plural and there are only four: this, that, these and those.
In the sentence <em>John wants that record</em>, <u><em>that</em></u> is working as a demonstrative pronoun because it is used to indicate a singular element that is far in distance.
