Challenges with mandatory fields after I have changed the Tab Name

Challenges with mandatory fields after I have changed the Tab Name

I have just started to use ZOHO CRM.  Our company works often with Charities and so we renamed one of the Tabs "Charities".  I was able to customize two other tabs and all of the associated fields.  When I attempted to change the "Last Name" field in Charities I found that I could not alter its "Mandatory" Status.  Through some research I have found that certain tabs cannot be made non-mandatory, for Quickbooks reasons.  My issue is that "Last Name"  Does not fit with the Charity Tab. Is there a way around this issue?