Diet is the biggie here. Couple your diet with some exercise and the weight will come off, but be realistic as to how much you will lose, as age plays a big part in that as well.
Others have stated this, but drop creamy salad dressings and mayonnaise on sandwiches. Go with good oil and vinegar or neat veggies, skip the sandwich too and go for veggies, fruit and the protein that would be in your sandwich. Cut out most of your carbs and starches. Have your carbs at breakfast, with fruit and protein. No bread, potatoes, rice or pastas at lunch or dinner. Add any exercise in and you'll drop weight.
Boom. Shape is made by your diet.
You will gain weight if you don't adjust your diet as you will likely feel hungrier.
I would also only drink water / tea / coffee. Drastically reduce the amount of alcohol you drink.

