Switching employers on Tier 2: WHICH FORM TYPE?

[onlooker]

While trying to book a same-day appointment online I am being required to choose form type from the list below:

CR1
CR2
CR3
CR4
CR5
EEA1
FLR (AF)
FLR (FP)
FLR (M)
FLR (O)
NTL
PBS Dependant (Tiers 1, 2 and 5) paper form
SET (AF)
SET (F)
SET (M)
SET (O)
Tier 1 (General)
Tier 5 Migrant paper form
TOC

The form itself has no mention of any of these abbreviations. Googling or HO website did not help. Any suggestions please?

I'm going to apply for Tier 2 General while being in country on Tier 2 General.