When a prospect is going to have a new manager you can use the function on the Prospect Team tab to Replace prospect manager. The new managers start date cannot overlap with the previous manager, but sometimes even when it doesn't an error is given that says the start can't come before the previous managers end date.
Download and install the latest service pack, which contains all fixes from previous service packs. If you are running an older version, download and install the latest version and then the service pack.
Steps to Duplicate
1. Open a Constituent 2. Select the Prospect tab > Prospect Team tab 3. Click Replace Prospect Manager 4. Leave all of the defaults, Choose any other manager for the required field 5. Save -- Error is given