A revocable trust avoids probate by effecting the transfer of assets during your lifetime to the trustee. This avoids the need to use the probate process to make the transfer after your death. The trustee has immediate authority to manage the trust assets at your death; appointment by the court is not necessary.
The “funding” of a revocable trust is critical to successfully avoid probate. Those persons who do not fully fund their trusts often need both a probate administration for the non-trust assets as well as a trust administration to completely distribute the assets. Because the revocable trust may not completely avoid probate, a simple “pour over” will is needed to transfer any probate assets to the trust after death.