Acts 10:15

And a voice came to him again the second time, What God has cleansed, do not call common.

καὶ φωνὴ πάλιν ἐκ δευτέρου πρὸς αὐτόν· Ἃ ὁ θεὸς ἐκαθάρισεν σὺ μὴ κοίνου.

Greek

Compare with the ASV

And a voice came unto him again the second time, What God hath cleansed, make not thou common.

What we did

We rendered the voice's command "do not call common," where the ASV has "make not thou common."

Why

κοίνου
is the present imperative of κοινόω, the verb formed from κοινός, "common." Its object is what God has already cleansed, and the command is about how Peter is to regard it.
Peter's own wording
In 10:28 Peter uses the same word with "say": μηδένα κοινὸν ἢ ἀκάθαρτον λέγειν, "that I should not call any man common or unclean." "Call common" matches the phrase Acts itself uses.
Two words in 10:14
Peter says he has never eaten anything κοινὸν καὶ ἀκάθαρτον, "common and unclean." κοινός is "common, ordinary"; ἀκάθαρτος is "unclean." The voice in 10:15 uses only the verb from κοινός.
More
The English keeps the two words distinct, "common" and "unclean," here and in 10:28.