It is possible to unmask paths to a LUN. Deleting the claim rules, which were created to assign the ownership of the paths to the MASK_PATH plugin, and unclaiming the paths from the plugin, does this. Understanding how the paths to a LUN are masked will be a good starting point for this task. Read the recipe Masking paths to a LUN before you begin.
The following flowchart provides a high-level overview of the unmasking procedure.