When item's date changes ,change its subitems' date to the same date + offset by this number column of days/weeks/months

video1.0<iframe src="https://www.loom.com/embed/300877282d534a7cb11e23a4503340e7" frameborder="0" width="1920" height="1440" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>14401920Loomhttps://www.loom.com14401920https://cdn.loom.com/sessions/thumbnails/300877282d534a7cb11e23a4503340e7-1ed2420c9ed2d38f.gif279.297When item's date changes ,change its subitems' date to the same date + offset by this number column of days/weeks/months