It is permissible for a wife to give her turn to a co-wife
حَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ، وَعَبْدُ بْنُ حُمَيْدٍ، جَمِيعًا عَنْ عَبْدِ الرَّزَّاقِ، عَنِ ابْنِ جُرَيْجٍ، بِهَذَا الإِسْنَادِ وَزَادَ قَالَ عَطَاءٌ كَانَتْ آخِرَهُنَّ مَوْتًا مَاتَتْ بِالْمَدِينَةِ .
Ibn Juraij narrated a hadith with the same chain of transmitters, and she (Hadrat Maimuna) was the last of them to die at Medina.