import re

text = """"This is a quote"
This is an end "partial-
quote" Here is more text.
This is an end "partial-
quote w/o more text
This is an "embedded" quote

"This is a quote"
This is an end "partial-
quote" Here is more text.
This is an end "partial-
quote w/o more text"
This is an "embedded" quote"""

print re.sub(r""""[^"\n]+?\n[^"\n]+?(?:"|$)\s*""", "\n", text, flags=re.M)