A.T. Robertson Commentary Galatians 4:20

"but I could wish to be present with you now, and to change my tone; for I am perplexed about you." — Galatians 4:20 (ASV)

I could with (ηθελον). Imperfect active, I was wishing like Agrippa's use of εβουλομην in Ac 25:22, "I was just wishing. I was longing to be present with you just now (αρτ)."

To change my voice (αλλαξα την φωνην μου). Paul could put his heart into his voice. The pen stands between them. He knew the power of his voice on their hearts. He had tried it before.

I am perplexed (απορουμα). I am at a loss and know not what to do. Απορεω is from α privative and πορος, way. I am lost at this distance from you.

About you (εν υμιν). In your cases. For this use of εν see 2 Corinthians 7:16; Galatians 1:24.