Is it for your family? If so you can. GO to main immigration in madinat khalifa. Near the petrol station you can find typing centre. Fill a visit visa extension form from there and got to main immigration office gate number 1 first floor(Captains office).Give the filled form to a person who is in the counter( his name is Abdul Rahman I guess) He will get the sign of Captain for 1 more month extension and will tell to come back next day( sometimes he may give that time itself depending on the croud).Then go to the visa stamping section which will be in the ground floor ( Before it was in gate number 4 now in gate number 1). And you can get the extension stamped.So times they may ask for air ticket for the extended date of travel and some times not. If so take a ticket and go back.Thats all. You can extend one more month after 7th month extension.ie a total of 8 months.