Why is this an issue?

Case statements are syntactic sugar for a series of conditionals that all test the same value for equality.

A case statement with only one item is functionally equivalent to a single if statement, and a case statement with only one item and an else is functionally equivalent to an if statement and a corresponding else.

In both these cases, using an if statement would be clearer.

How to fix it

If it is a case statement with one item, replace it with an if statement using the same condition.

// Noncompliant
case MyNum of
  0: Exit;
end;

// Compliant
if MyNum = 0 then begin
  Exit;
end;

If it is a case statement with one item and an else, replace the item with an if statement using the same condition and a corresponding identical else.

case MyNum of
  0: Exit;
  else begin
    Writeln('Not 0!');
  end;
end;

if MyNum = 0 then begin
  Exit;
end
else begin
  Writeln('Not 0!');
end;