Any time between 5 and 7 months, depending on the dog. If you feel that she can make the transistion then give it a go by gradually reducing one meal & increasing the other two accordingly.
__________________ "The best dog is the one you take home with you"
Location: Northampton
I found that my dog was not eating his lunch meal so at around 7 months dropped it and fed twice am at 9am to 10am then 10pm at night this works well for him. Just go with your instinct and reduce when you feel it to be right .xx