How to convert a pivot back to dataframe in the same format

Question

I have created a pivot table out of my original dataframe

id	label	value
1	abc	0.2
2	efg	0.4
3	abc	0.2
2	abc	0.4
1	efg	0.2
3	efg	0.4

df.pivot(index="id", columns="label", values="value")

which converts the original df to:

label

id	abc	efg
1	0.2	0.2
2	0.4	0.4
3	0.2	0.4

Now I would like to convert the above dataframe back to original dataframe, reset_index() is not the option for me here.