custody changes, a change in custody of
For example, a bump test should be conducted if there is a change in custody of the monitor, which could even include one employee giving the device to another employee, who will be working in a different work setting or environment during the same shift.

Australian Gas Detection Standards - Make Your Workplace Safer
Recent advice from the International Safety Equipment Association extends this to carrying out a function test if there is a change in custody of the equipment, which could include one user handing over a detector to another.
Change in custody of the detector, like shift changes when the detector is “handed off” from one user to another.