word for temporarily ordering a worker to a new position because of an emergency

Solution 1:

While a hypernym,

second in one of its senses is usually the result of a perceived need:

Definition of second (Entry 5 of 5) [transitive verb] ...

3\ si-​ˈkänd \ [OALD has /sɪˈkɑːnd/] chiefly British:

to release (someone, such as a military officer) from a regularly assigned position for temporary duty with another unit or organization

[Merriam-Webster]

An example from Deloitte [2017]:

  • In 2008, a UK retailer (UK Co) set up an Indian joint venture company (JV Co) with a large Indian retailer, with a view to expanding the presence of the UK company in India. JV Co thereafter concluded an agreement with UK Co, under which several UK Co employees were seconded to India to help set up the Indian business.

And a COVID-related example from BMJ Emergency Medicine Journal:

To ensure adequate manpower, leave was embargoed and doctors from other departments were seconded to DEM.

Solution 2:

An emergency reassignment would be called a redeployment. Although military in origin, it is also used generally:

re·de·ploy or reassign temporarily)

v. re·de·ployed, re·de·ploy·ing, re·de·ploys

v.tr.

  1. To deploy (personnel, especially military forces) to a different place or on a different assignment.

  2. To put to a different use or action; deploy in a different way: redeploy the company's resources.

v.intr. To be deployed to a different area or assignment.

AHD https://www.ahdictionary.com/word/search.html?q=redeploy

Solution 3:

The US military has an acronym (no surprise) for exactly this situation: TDY, short for Temporary Duty. I regularly worked with people on TDY to our base for training or support. It sounds like a good analog to what you describe.

Unfortunately, while anyone who's had military experience will get it right away, no one else will unless you manage to spread it. (-: