You may use the "Rename Series" function to rename articles in series.
 
Right click on the selected node. Muti-selection is allowable. In the context menu, select "Rename Series" and then a dialog for renaming articles in series will be displayed:
 
 
Template: Specify a template for renaming nodes.  Template can contain */#.  * will be replaced with the old node name and # will be replaced with a sequence.
Replace '#' with: Select a sequence, which is used to replace '#'.
Start at: The position at which the selected sequence starts.
Find what: Find the text in the titles of nodes. 
Replace with:Replace the found text with other text. If blank, the found text will be deleted. 
Click "Re-select Nodes " to select the nodes that need to be re-named again. 
 
New names will be shown in the preview list.