Sample exchange in preset kits


is it not possible to exchange a samples in GA presetkit? I could only exchange or put another sample in a “free” Agent.
If i choose a preset i could only change teh sound of the instruments. (GA4) Is this possilble in GA5?

no one? May be I have to specify a little bit.
In all Agent i can exchange the sample ( incl. chargeable content like Metronomic cinema and other soundsets) exept the Accoustic Agent ;Accoustic Agent SE ; Percussion Agent; Rock Agent. In this Agents i can only tweak the sound of the instruments.