Can Erdogan safeguard continued Ukrainian shipping in the Black sea?

The European Union's top diplomat has called on Turkey to change its trade policy towards Russia, after the invasion of Ukraine. EU Foreign policy chief Josep Borrell said Turkey's refusal to join the EU in sanctioning Russia was "a growing cause for concern".
It comes as Turkish President Rejep Tayyip Erdogan plans to speak separately to both Russian President Vladimir Putin and Ukraine's President Vologdymr Zelenskyy to discuss strengthening the Black Sea grain deal. The agreement allows Ukrainian grain to be exported via a Black Sea corridor.