2 options with Excel 365 & Training data formatted as a table named Training (not mandatory, will work the same with a range)
in E8:
=IF(ISBLANK(B8), "",
SUBSTITUTE(
TEXTJOIN(", ",TRUE,IF(INDEX(Training,MATCH(B8,Training[NAMES],0),0)<>0,Training[#Headers],"")),
"NAMES, ",""
)
)
in E9:
=IF(ISBLANK(B8), "",
SUBSTITUTE(
TEXTJOIN(", ",TRUE,IF(FILTER(Training,Training[NAMES]=B8)<>0,Training[#Headers],"")),
"NAMES, ",""
)
)
Corresponding workbook available here