A more thorough explanation:

Delectus personae is a Latin term that means "choice of the person." It refers to the rule that when personal relationships are important, a person cannot be forced to associate with another person.

For example, if you are starting a business with a partner, you have the right to accept or reject a candidate proposed as a new partner. This is because personal relationships are important in a business partnership, and you want to make sure you can work well with your partner.

A delegate is someone who represents or acts for another person or a group. In parliamentary law, a delegate is a voting member of a convention.

For example, if you are unable to attend a convention, you can send a delegate to vote on your behalf. The delegate will represent your interests and vote according to your wishes.

There are two types of delegates: instructed and uninstructed. An instructed delegate is bound to vote according to their constituency's expressed wishes. In contrast, an uninstructed delegate is not given specific instructions and may vote according to their conscience.