Attempting to alter another dreamer or their dream against their will requires winning a contested Lucid Dreaming check. The one attempting to not be changes gets +5 to this check in that case.
You might want to rephrase this a bit and note what kind of bonus is gained.

For example:

Attempting to alter another dreamer or its dream against its will requires winning a contested Lucid Dreaming check. The one attempting not to be changed gains a +5 Insight bonus to this check in that case.

Debby