How to change the url for a map service in an existing web map

Discussion created by steinj14 on Aug 2, 2013
Latest reply on Aug 5, 2013 by astauffer-esristaff
Maybe I'm missing something obvious, but I have an existing web map and I want to change the url for a map layer that's already been added.  How do I do this?  I don't want to delete the "old" layer and add the "new" layer because I have customized the layer in the web map. Can anyone enlighten me?
Thanks, Joan