"The Messenger of Allah said to a woman from among the Ansar: 'When it is Ramadan, perform 'Umrah then, for 'Umrah during it is equivalent to Hajj." (Using translation from Nasāʾī 2110)
"إذا كانَ رمضانُ فاعْتمرِى فيه، فإنَّ عُمْرةً فيه تَعْدِلُ حجَّةً".