Az acting up ugyanaz, mint a secondment vagy temporary promotion, ez magyarul átmeneti előléptetés (átmeneti áthelyezés magasabb beosztásba).

"(Business / Industrial Relations & HR Terms) Brit a temporary transfer to another job or post within the same organization."
http://www.thefreedictionary.com/secondment

Az erről szóló irat a secondment letter, más szavakkal acting up letter.

"Acting up arrangements are designed to meet short term needs. After acting up for 56 days, a member will be moved from acting duties to temporary promotion unless he/she is not qualified for promotion or there is an overwhelming operational emergency.
A member who has acted up in a higher rank for 10 complete days (or 80 hours) in a 12 month period from 1 April will be paid for each further complete day/shift at the lowest rate to which s/he would be entitled on promotion to the higher rank.
The 10 day qualifying period need not be continuous but it is included in the calculation of the 56 day maximum; the remainder of the 56 day period (from day 11 to 56) must be continuous. Continuity is preserved if a member is not at work as a result of a routine short term absence (and may be preserved in to the following year).
A period of acting up is not reckonable for pay increments in the higher rank but is reckonable as service in the substantive rank. The additional salary is not pensionable.
A member who is acting up will continue to receive their CRTP. A constable or sergeant acting up to inspector or above is not entitled to overtime payments. If however such a member is required to do duty on a rostered rest day or a public holiday he/she will be entitled in the normal way."
http://www.glospolfed.org.uk/rules-and-regs/quick-reference-...

"This procedure explains the process through which Hampshire
Constabulary Police Officers will be entitled to receive a payment for
performing ‘acting up’ duties or be temporarily promoted."
http://www.hampshire.police.uk/nr/rdonlyres/e7f37f3f-89eb-4c...

"Conditions handbook cover acting up or temporary moves to a higher pay..."
www.yorksandhumber.nhs.uk/document.php?o=3205