Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 - Manual (Page 48)

Configuring the Scanner through LIST
Chapter 2
2-22
Reconfiguration
This selection implements changes that you have made in LIST for channel
0. If channel 0 is being used when you reconfigure it, the changes are not
implemented until communication on the channel is terminated and then
re-established.
An asterisk appears next to Reconfigure when a change has been made to
any of the channel 0 parameters. The asterisk is removed after a successful
reconfigure.