Please don't change the format of dates. As a general rule, if an article has evolved using predominantly one format, the dates should be left in the format...

Optional current franchise history --> | name1 = | dates1 = | name2 = | dates2 = | name3 = | dates3 = | name4 = | dates4 = | name5 = | dates5 = | name6...

Optional current franchise history --> | name1 = | dates1 = | name2 = | dates2 = | name3 = | dates3 = | name4 = | dates4 = | name5 = | dates5 = | name6...

Optional current franchise history --> | name1 = | dates1 = | name2 = | dates2 = | name3 = | dates3 = | name4 = | dates4 = | name5 = | dates5 = | name6...