Giving a shift away when no one can take it outright
Updated October 13, 2026 · with an example to try
When no one can take your shift outright, a colleague who is busy next to it may take it if someone else covers one of their shifts. That last person picks up the extra shift; everyone in the middle keeps the same number. Kidney exchange runs long chains on the same idea.
Give a shift away
Example · runs in your browser; nothing you enter is sent
You want to give Saturday night away. Tap any day to change it (off, day, night), change what a colleague won't work, or whether they pick up extra shifts.
You
Ava
Ben
Cy
Dee
Who can take your Sat, Nov 7 night outright
No one can take it outright.
- Ava doesn't work nights.
- Ben doesn't work weekends.
- Cy would have 0 hours off before it.
- Dee already works then.
Or give it away through a colleague
Everyone in the middle keeps the same number of shifts; the last person picks one up.
Cy takes your shift if Ava covers Cy's Sat, Nov 7 day.
- Cy: 84 hours off before it, 36 after
- Ava: 36 hours off before it, 60 after
Made-up schedules for two weeks from Monday, November 2, 2026 (Mon, Nov 2 to Sun, Nov 15): days 07:00 to 19:00, nights 19:00 to 07:00. Every shift someone picks up is checked for overlaps and at least 11 hours off before and after it. In place of the patterns Capillary reads from a real schedule, each sample colleague can refuse one kind of shift.
In the sample, no one can take your Saturday night outright. Ava doesn't work nights, Ben doesn't work weekends, Cy works Saturday's day shift and doesn't pick up extra shifts, and Dee already works then. Cy takes your night if Ava covers Cy's Saturday day shift. Untick Picks up extra shifts for Ava, and the line grows: Ava takes Cy's day shift and hands one of Ava's weekday day shifts to Ben.
How a giveaway down a line works
- 1
A colleague takes your shift
Colleague A takes your shift and hands on one of their own, often the one that sits too close to yours.
- 2
Someone covers theirs
Colleague B takes A's shift. B can hand on one of theirs in turn, down a line of up to five colleagues in Find a swap.
- 3
The last person picks one up
The last colleague takes the final shift outright. Everyone in the middle gives one shift and gets one; only the last person works one more, and you one fewer.
Each person's new shift passes the same checks as any swap: no overlap with their other shifts, and enough rest before and after it.
Why chains help
In kidney exchange, a chain starts with an altruistic donor: someone who gives a kidney without a patient of their own. In 2007, one such donor started a chain of 10 transplants, coordinated over 8 months across six transplant centers in five states. Ashlagi, Gamarnik, Rees and Roth later showed that "large cycles of exchange or long chains can significantly increase efficiency when the opportunities for exchange are sparse."
A colleague who picks up an extra shift plays the donor's part: they give their time without getting a shift back, and their yes lets a line of colleagues move. In Capillary's simulation on made-up groups of 6 to 10 people, 33 giveaways had no likely taker and no likely way through one colleague; a longer line found a likely way out for 10 of them, mostly weekend nights.
Making it happen
- 1
Ask the whole line
It only works if everyone agrees, so ask them all, starting with whoever is least likely to say yes. In Find a swap, Send a swap request gives each person a link and shows you every answer.
- 2
Enter it from the end of the line
First the last person picks up their shift, then each person takes the next, and your shift goes last. That way no one holds two shifts that clash, even for a moment.
Common questions
- Is it fair to the people in the middle?
- They keep the same number of shifts: each takes one and hands one on. Only the last person works an extra shift, and they chose to.
- How long can the line be?
- Find a swap looks down a line of up to five colleagues, and looks for longer lines only while shorter ones give fewer than three likely ways out.
Find swaps in your own group's schedule.
Find a swap is free for clinicians. Bring in your group's schedule from its calendar link, and Capillary checks every swap for overlaps and rest for both people, puts the colleagues most likely to say yes first, and finds three-way swaps, and bigger ones where smaller swaps run short. Your copy is yours: no one in your department or hospital sees it (who can see what).