Give this a try:
with basedata as ( -- creating test data
select
*
from
(values ('INTERNAL COMMUNICATIONS:' + Char(13) + 'Blah blah blah blah'),
('NOTES/MEMOS:' + Char(13) + 'This is a random note. It could go on for up to 200+ charaters, etc.'),
('INTERNAL COMMUNICATIONS:' + Char(10) + 'Blah blah blah blah'),
('NOTES/MEMOS:' + Char(10) + 'This is a random note. It could go on for up to 200+ charaters, etc.'))dt(TestStr)
)
select
*,
left(TestStr,patindex('%[' + char(13) + char(10) + ']%', TestStr) - 1)
from
basedata