Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions.
As to what follows:
With regards to answering your question we say, success is by Allah Almighty.
There are two opinions regarding this issue which are narrations from Ahmad (may Allah have mercy on him):
First: It is permissible and correct for a person to change from praying alone to becoming an Imam.
Second: It is neither permissible nor correct. This is the opinion held by the Malikites scholars and also the more correct of the two narrations.
What appears to be the most correct view according to me is the second opinion which says it is not permissible to change from praying alone and becoming an Imam because there is no written text which supports this.
The principle for acts of worship is that they should be based on textual evidence. However a Prayer that has been done already cannot be repeated.
And Allah knows best.
Your brother,
Dr. Khalid al-Muslih
08 / 04 / 1425 AH