With a pour-over Last Will and Testament, you create a trust, then you state in your Last Will and Testament, that you want the personal property in your estate at the time of your death to be distributed to the Trustee of the trust. Most people do not usually put all of their assets into trusts for reasons of liquidity, convenience, or simply because they did not get around to doing so before they died.
Once you die, your property is subject to probate until such time as the pour-over clause is applied, and the estate assets “pour” into the trust. The trust instrument must be either in existence at the time when the will with the pour-over clause is executed, or executed along with the will to be a valid pour-over gift. The pour-over clause protects personal property not previously placed in a trust by pouring it into the previously established trust.
This applies to personal property only. A pour-over Last Will and Testament cannot “pour” real estate into the trust. You must make sure that your real estate is transferred to the trust before you die.