I can never manage to remember how to do this. Simple enough, how do you update your login credentials in Remote Desktop Manager ( RDCMAN )?

Right click on the root node and select Properties.

Select the Security Settings tab, then click on Source: default settings group.
A new window will open, in it, select the Profile Management tab.
Select the account you want to update, click the Edit button on right, then click Ok on the bottom.

All done.