How can I give someone access to another agents' account to pay their balances?
This can be accomplished through the use of the broker/team affiliation tool. You can create a profile for Person A and list them as an administrator. Add a text code. This is how that will look:
Then go to Person B's profile and designate Person B as his administrator by adding his/her text code. Now Person A can use his/her own login to access Person B's projects.