Voice Training- formerly known as elocution, is a quick and simple way to get rid of an accent or speech defect.
Losing an accent and learning to speak with good received pronunciation, BBC English, is not as difficult as you might think.
We learn to speak without needing any formal training and that is because we simply learn to mimic those around us. If you want to change the way you speak then mimicking others who speak the way you would like to speak is a good place to start. Listen to as much well-spoken English as you possibly can, listen to actors and actresses being interviewed on You Tube and practice imitating them. Remember we learned to speak by hearing and reproducing what we heard. Use this same technique to make change – fake it, until you make it.
Audio books and BBC radio 4 programmes are an excellent source of good diction. Find books that are read by someone of your gender and age and then simply copy what you hear for practise.