United threatened to report Real to Fifa earlier this week over their public pursuit of Ronaldo and Calderon now seems to have accepted defeat.
Calderon attempted to cool the row on Wednesday by stressing that Real would not try to sweet-talk Ronaldo into leaving Old Trafford.
He has reiterated that Real do not want to damage their relationship with United and admitted there is little point in tracking Ronaldo further.
"You can't buy what the owner does not want to sell," Calderon said on Sky Sports News.
"Real Madrid are friends with Manchester United and we do not want to fall out with them."
