I've done this a couple of different ways.
1. Move, or rename the comp you wish to replace in Pr.
Open Pr, and link to your preferred comp when prompted.
I only use this method when I am certain that both the new
and original comps are the same length, fps & aspect.
2. Import your new comp to Pr via Dynamic Link,
then Alt-Drag the comp to the timeline to replace the original.