Embarrassed when packing cereal. Change logo! (7)
I believe the answer is:
rebrand
'change logo' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'embarrassed when packing cereal' is the wordplay.
'embarrassed when' becomes 'red' (I've seen this before. I am not sure about the 'when' bit.).
'packing' is an insertion indicator.
'cereal' becomes 'bran' (type of cereal).
'red' placed around 'bran' is 'REBRAND'.
Can you help me to learn more?
(Other definitions for rebrand that I've seen before include "Change the corporate image of" , "Give new label to" .)