Officiating, according to its ordinary connotation, the word 'officiating' is generally used when a servant having held one post permanently of substantively, is appointed to a post in a higher rank, but not permanently or substantively, while still retaining his lien on his substantive post, Arun Kumar Chatterjee v. South Eastern Railway, AIR 1985 SC 482 (485): (1985) 2 SCC 451. (1983) 3 SCR 18. (Railway Establishment Manual, R. 312)
The word 'officiating' is generally used when a servant having held one post permanently or substantively is appointed to a post in a higher rank, but not permanently or substantively, while still retaining his lien on his substantive post i.e. officiating in that post till his confirmation, Arum Kumar v. South Eastern Railway, AIR 1985 SC 482.