I can take calls anytime as long as it's not during my work hours.
I'm up for phone calls anytime as long as it's not during my work hours.
Feel free to call me anytime as long as it's not during my work hours.
Hi there!
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文を分解して説明すると以下の通りのようになります。
"...as long as it's not during my work hours"：「仕事中でなければ〜」
"I can take calls anytime"：「いつでも電話に出れるよ」
"I'm up for phone calls anytime"：「いつでも電話でお話しできるよ」
"Feel free to call me anytime"：「いつでも気軽に電話してね」
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Hope this helps!
日本 
