Go to the appropriate Manuscript table. Note the number that is assigned in the upper left corner of the red screen (in the example below, the number 1032)
Next go to the Microfilm table. Enter the number you recorded in the box that reads “Override Holding on Label” in the upper right corner of the Microfilm: Main layout.
Then click on a blue part of the screen. This should cause the call number to be reassigned based on the manuscript you identified in the “Override holding” box.