The architect should issue a clarification to the contractor explaining the mistake and providing the correct finish tag to be used.
The architect should proceed by issuing a clarification to the contractor to address the incorrect finish tag on the bathroom elevation.
The clarification can be sent in writing, either through email or a formal letter, explaining the mistake and providing the correct finish tag to be used.
It is essential to communicate this clarification prior to the beginning of work in the affected area to avoid any confusion or errors during construction.