Hi @tscott07 ,
Do you want to transfer person field display name from "firstname lastname" to "lastname, firstname"?
If you want to directly use person field in one item, you could try this formula:
Last(Split(ThisItem.personfield.DisplayName," ")).Result&","&
//lastname,
First(Split(ThisItem.personfield.DisplayName," ")).Result
//firstname
If you want to select person for this field in combo box , display the selected value as "lastname, firstname", you could try this formula:
Last(Split(personfieldcomboboxname.Selected.DisplayName," ")).Result&","&
//lastname,
First(Split(personfieldcomboboxname.Selected.DisplayName," ")).Result
//firstname
Best regards,