newDF = pd.DataFrame() #creates a new dataframe that's empty
newDF = newDF.append(oldDF, ignore_index = True) # ignoring index is optional
# try printing some data from newDF
print newDF.head() #again optional 

df.empty == True

df_empty = pd.DataFrame({'A' : []})
df_empty.empty # True

>>> df_empty = pd.DataFrame({'A' : []})
>>> df_empty
Empty DataFrame
Columns: [A]
Index: []
>>> df_empty.empty
True