The change made on the source replica wins. The change applier passes the change to the SaveChange or SaveChangeWithChangeUnits method and specifies a save action of SSA_UPDATE_VERSION_AND_DATA. The change is applied to the destination replica exactly like any non-conflicting change.
SRA_MERGE
Merge the data from the source item into the destination item. The change applier passes the source replica's change data to the SaveChange or SaveChangeWithChangeUnits method and specifies a save action of SSA_UPDATE_VERSION_AND_MERGE_DATA. The destination provider combines the source item data and the destination item data, and applies the result to the destination replica.
The members of SYNC_RESOLVE_ACTION specify the action that the change applier uses to resolve a concurrency conflict. Concurrency conflicts occur when the same item or change unit is changed on two different replicas that are later synchronized. For more information on concurrency conflicts, see Detecting and Resolving Concurrency Conflicts.