If it is always 4 elements, change the diagram constants and indicators accordingly.
In the worst case, you need to unbundle and rebundle, leaving some of the unused data at a sentinel value (e.g. NaN).
Who wrote these subVIs? Are they from a toolkit or home-made? If home-made, create a typedef of the correct cluster and link all instances to it. This will allow you to change the cluster later (e.g. with fewer or more elements) and all instances will update.