Conversion from IFRS to Other standard

This question may not be directly related to P2, but what happens if a company (i.e- Subsidiary) produces its financial statements in IFRS, but its parent company resides in another country producing financial statements under other standards.

For example a UK subsidiary producing financial statements under IFRS has a parent in US where financial statements are prepared under US GAAP.

Is there any guidance on the conversion from Accounting bodies?