Correction of values for converted prospects

Correction of values for converted prospects

Hello,

I'm having problems in Zoho Reports with duplicated values that appears in the report I create.
I've seen that it is due to changes that have been made in a specific field after  converting the lead.

For ex:
- Before converting, the lead contry said: México (with accent)
- After converting, we changed it to: Mexico (because we saw it was better to avoid accents).

Is it possible to correct the "table" value of an already converted lead?

thanks
Efrain