A change-out handle system is provided for releasably coupling two elongated, axially relatively displaceable functional parts to a medical instrument unit. The change-out handle system includes a first and a second handle part disposed axially relatively displaceably, a first coupler for releasably axially rigidly immovably coupling a first of the two functional parts to the first handle part and a second coupler for releasably, axially rigidly immovably coupling the second of the two functional parts to the second handle part. The second handle part has a pass-through opening for passing at least the first of the two functional parts. The change-out handle system can be used, for example, for medical solids trapping instruments.