What does it mean to "have ijazah to give ijazah" and to "have ijazah but UNABLE to give ijazah"?

Question
Bismillah wa Alhamdulillah wa As-Salaat wa As-Salaam 'alaa Rasoolillah
As-Salaamu 'Alaikum wa Rahmatullahi wa Barakaatuhu!
What does it mean to "have ijazah to give ijazah" and to "have ijazah but UNABLE to give ijazah"?
Jazaakumullahu khairan!
wa 'Alaikumus-Salaamu wa Rahmatullahi wa Barakaatuhu!

Answer
Wa alaikum assalaam wa rahmatullahi wa barakaatuh,
Almost all ijaazaat are in recitation certify that the one getting ijaazah can read completely correctly by memory and has been given permission by the one giving the ijaazah to pass this knowledge on to others.  This would be have an ijaazah to give an ijaazah.

There are very few who are given an ijaazah that their recitation is completely correct, yet unable to give others ijaazah, but it can be in the case of one who can read correclty, but is not able to hear and describe the mistakes of others and correct them.
Wa iyyaaakum. 
Wa assalaam alaikum wa rahmatullahi wa barakatuh