That really doesn't make sense. Like any collection, the Queue is as big as the number of items it contains. Why would you want to change the size of it? The only reason I can think of is to put more items in it. Well, if you want to put more items in it then go ahead and do so. The act of adding the items will make the collection grow.
In the case of an array, you might specify its size as 10, which means that it initially has 10 elements that are all Nothing. You might set one of those elements but the array still has 10 elements, 9 of which are Nothing. You might set another element but the array still has 10 elements. So on and so forth until all 10 elements have been set. If you want to add an eleventh object you can't, other than by replacing one of the existing objects, in which case the array still has 10 elements. You could call Array.Resize or use ReDim Preserve and specify a size greater than 10, e.g. 20, in which case an new array with 20 elements would be created and the 10 elements of the original array copied into the first 10 elements of the new array.
The Queue is not like that at all. When you create it it is empty, i.e. it contains no items. When you Enqueue an item the Queue now contains 1 item. If you Enqueue another item the Queue now contains 2 items. If you Dequeue an item then the Queue now has 1 item. Just like the stretchy bag I mentioned earlier, the collection grows and shrinks inherently as you add and remove items. Just like the egg carton I mentioned earlier, the array always has the same number of elements as you specified when you created it, even if some of them are empty.
Are we clear now? If not, please do as I asked last time and explain WHAT YOU ARE TRYING TO ACHIEVE rather than how you are trying to achieve it. Trying to change the size of a Queue is the method by which you are trying to implement some functionality. I want to know what that functionality is because, if I know that, then I can explain how to achieve it without trying to do something that is impossible. If I kept asking you how to walk across the floor of the Pacific Ocean could you tell me how to do it? Would there be any point when what I was actually trying to achieve was to get to the United States? Why do I need to explain the difference between what and how?