I came across an interesting problem today and I will mention it here verbatim and try to solve it. The question was how do you delete a node from a singly linked list if the head is not given. So we only have the current node and the node has to be freed. Futhermore, the singly linked list is not a circular list that we can traverse to find the head.  Since we don't know the head and we can't traverse the list, we don't know the previous node to update its reference.
By deleting the node and not the knowing the previous node, we have broken the list and created dangling references. So one solution I suggested was that we treat the list as immutable physically and overlay a layer that shows the logical list by skipping over the nodes that are deleted. So we pass through the nodes that are deleted during traversal without doing any operation on them. We can keep additional state per node in a wrapper that says if it is deleted or not. Another approach is to scan the memory for all occurance of the current pointer and set it to null now that the current node is freed though this could break users of the structures that may not be expecting a null pointer where it was previously expecting a valid pointer. That may depend on how the list is used.