People ask me if I do 'accent reduction'. I tell them that accents are good and they contribute to an interesting world. They only become a problem when they interfere with meaning. I can help people with specific sound confusions such as v/w or th/s and help them to lengthen short vowels or make a vowel sound more round but I don't particularly like calling it accent reduction.
Many years ago I used to run specific classes for migrant women. it was a mixture of job seeking and confidence building. We used to visit an energetic, larger than life Senator in the NSW Parliament - an Italian woman called Franca Arena. Franca spoke and acted enthusiastically about everything she did. After a visit and a 'pep' talk by Franca, one of my students said to me that she was amazed to see such an important woman talking with such a heavy accent.
People can make their 'accent' clearer but it requires practise, practise and more practise. If you commit to a pronunciation course change will come provided you practise and record and self correct regularly.