The employer should reassess promptly because the original specialized-knowledge basis may no longer fit.
Update the description with the work
Treat it as a material change and handle it when it happens, not at the next extension. The approval rests on a described role; once the daily work becomes translating and formatting documents the receiving site could hand to any bilingual contractor, the basis that supported it has gone, and an old approval notice does not keep proving a fact that has changed. The practical sequence is short: write down what the transferee now does, who directs it and at which site; compare that against the duty description filed with the petition; and where the difference is substantive, have the employer take advice on whether an amended petition is needed before the new pattern settles in.
Two dates belong in a diary. The approved validity period ends when it ends - a deferred commissioning does not push it outward - so any extension should be prepared months ahead on the facts as they stand then. Separately, time already held in L-1B counts toward a five-year ceiling that no extension passes, so a transferee approaching it needs that conversation earlier still.
Pressure from a plant schedule is a commercial fact, not a reason for the description to stay out of date. Two other things must remain true for the whole period: the qualifying parent, branch, subsidiary or affiliate relationship between two actively trading entities, and knowledge that is still special to this organisation or advanced knowledge of its processes rather than general trade skill; and if the work moves to an unaffiliated client's premises the petitioner must keep control of it and the placement must not become labour for hire.