You have the options to Edit an external login's Gardiant profile and Manage their Access to the employer(s):
If an external user has access to multiple employers at the same time, when you Manage their Access, you will be given the option to either remove their access from the employer you are currently accessing, or remove their access from all the employers:
*Very important* Any updates to the external user’s profile can take up to 24 hours to be reflected on their end.