st Christmas cryptic

[granny grump]

I am pants at cryptic crosswords and I am stumped on the last 8 - can any one please put me out of my misery?

15aRepeat treat that is organised (7) ??e?a??
20a Reindeer tail cut to a point (4) ?c??
81a Come to a party (4) ?a?e
83a Want to change vital part of panto dame (7) ??a???y (*******?)
9d The charm that robins hold for us (3) o??
12d The pudding may be boiled (5) s????
75dDorothy may give a party with drink we hear (3) d? (Dot? if so why?)
76d One of those the shepherds watched from the West (3) e??

As always all help very gratefully received

[JMR27]

15a iterate - ang treat + i.e.
20a Scut
81a wake

[THECORBYLOON]

76 is ewe "...from thE WEst"

[JMR27]

83a ******* - anag want + ke
9d ....rOBIn ...obi
12d sweet
75d Dot (short for Dorothy ...party = do + t (sounds liketea)

[netkey]

75 dot
do = party
t = tea (we hear)

[JMR27]

oh for goodness sake...83a 1st letter is T, 2nd W, 3rd A, 4thN + key

[spitza]

12d sweet?

[granny grump]

Thankyou JMR27, THECORBYLOON, and netkey - the answers all seem so obvious when they are explained - I just get a mental block whenver I see 'cryptic'