CREATE TABLE table_73367 ("Former country name" TEXT, "Former codes" TEXT, "Period of validity" TEXT, "ISO 3166-3 code" TEXT, "New country names and codes" TEXT)

Name the former codes for merged into panama ( pa , pan , 591 )
SELECT "Former codes" FROM table_73367 WHERE "New country names and codes" = 'Merged into Panama ( PA , PAN , 591 )'
SELECT "Former codes" FROM "table_73367" WHERE "New country names and codes" = 'Merged into Panama ( PA , PAN , 591 )'