Resumption preserves the valid earlier portion of prayer, while restarting begins with a new opening takbir. Restarting is preferred even where resumption is technically allowed.
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Resumption versus restarting
Hadath during Prayer: Building, Restarting and Twelve Final-Sitting Cases
Resumption preserves the valid earlier portion of prayer, while restarting begins with a new opening takbir. Restarting is preferred even where resumption is technically allowed.