In base R, you can do :
names(assessment)[grepl('^Org.*Type$', names(assessment), ignore.case = TRUE)] <- 'OrgType'
If you are interested in tidyverse
solution you can try :
library(dplyr)
library(stringr)
assessment %>%
rename_with(~str_detect(.,regex('^Org.*Type$', ignore_case = TRUE)), 'OrgType')
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