In advance and Pre-existent

In advance adjective - Situated ahead or going before.

Pre-existent and in advance are semantically related In some cases you can replace phrase "Pre-existent" with "In advance", this phrases are similar.

Pre-existent adjective - Existing previously or before something.

In advance and pre-existent are semantically related in sooner than expected topic. Sometimes you can use "In advance" instead an adjective phrase "Pre-existent".