Dear Srs. I have a valid Schengen visa type B, with multiple entries and valid till next year, this time, I'm outside from my country of origin due to my work, Now I'm going to meet my family in Madrid then go Paris for a short vacation and then I continue my job travel to Africa and my family will go back to my country, so How can I extend my 5 days entry visa to 20 more days without going out of Shengen territory?. (my family have a 60 days valid visa)