No Catholic Church can be established without a titular. “As soon as its construction is properly completed,” says canon law 1217, “a new church is to be dedicated or at least blessed as soon as possible.” Further, “Each church is to have its own title which cannot be changed after its dedication” 1218. This you may find interesting since it is the case of many parishes merging and the name of the parish community changing.
My home parish was Sacred Heart. It was a small Slovenian parish that was combined with St. Mary, and even smaller Polish community. The two congregations became one, they changed from a nationality parishes to a parish with boundaries, and they now meet under the new title of “Prince of Peace.” Soon the parishes of St. Bernard and St. Mary will combine to become St. Bernard/St. Mary. Interestingly enough however this does not affect the name of the church buildings in which these congregations meet. One simply cannot change the titular of a building once it has been consecrated. “So sorry Mary, we are done with you. We switching to Prince of Peace like an NFL team switching cities.” So the building in which Prince of Peace meets is still titled Sacred Heart and the Sts. B & M building will still be officially known as St. Bernard (though if anyone actually makes use of those names we will see) though the congregation that meets within its walls may change.
So there is no need and in actuality it would be wrong to obliterate the name from the building altogether. Remember those grand old bank buildings that had their names etched in stone? “The First Federated Money Bank” or some such thing? When we went through a flurry of sales and bank name changes somebody would take some cement, climb to the top of the building and fill in the letters for the name of the bank and the building changed. If there were such markings on a church building there would be no need to fill in the letters because unlike the bank, the church building still retains its name.