Working on all the days of the week is permissible, in Ramadaan and at other times. Saturdays and Sundays are not days when working is forbidden for Muslims.
The Muslim’s main concern should not be earning money and working at the expense of his prayer and fasting. So if a Muslim can reduce his worldly work without that causing harm to him or anyone else, then this is wise and is a good idea, to free the Muslim during this month to worship Allaah by fasting, praying qiyaam and reading Qur’aan.
And Allaah knows best.