Replace elements in array

I apologize if the question is very stupid. I am quite familiar with the basic functions of matlab, but I do not know such a function. Maybe there isn't one, which is why I'm asking. I'm looking for the best algorithm to do this. Let A be an array of numbers. I have provided an example below. Vector A is not symmetric and needs an algorithm that repeats the lines below. If there is no such thing, then thank you for your attention.

A = [1, 2, 3, 4, 5, 6];
aa = A(2);  
A(2) = A(3);
A(3) = aa;

Answer 1

[Adam Danz]

I wouldn't call this an algorithm. It's just indexing. If something more robust is needed we'll need a more detailed description or set of rules to follow.

A = [1, 2, 3, 4, 5, 6];
A = A([1,3,2,4,5,6])

A = 1×6

1 3 2 4 5 6

> Vector A is a vector of unknown length and content, in which the k-th and j-th elements change.

A = [1, 2, 3, 4, 5, 6];
k = 4; 
j = 2; 
A([k,j]) = A([j,k])

A = 1×6

1 4 3 2 5 6

[Igor Arkhandeev]

Thanks for the answer. I will try to describe my problem a little more. Vector A is a vector of unknown length and content, in which the k-th and j-th elements change.

[Adam Danz]

See updated answer.