Mnangagwa’s lawyer, Tinomudaishe Chinyoka, has hinted that ZANU-PF will be pushing for the CCC who resign to be replace directly instead of going for a by-election.
This is reportedly in anticipation of a mass resignation by CCC following the resignation of CCC President, Nelson Chamisa.

Below is the full statement by Chinyoka:
RESIGNATIONS – MY UNPOPULAR OPINION The full meaning of s129(1)(k) is that an MP in Parliament belongs to the political party that sponsored them at the last election. That is why parties get the right to recall people who have left the party.

The constitution gives the political party the right to not lose its seat by virtue of a member leaving the party, but the Electoral Act yanks that right away by requiring a by-election to fill the vacancy.

This in my view makes the right in section 129(1)(k) weaker, because anything can happen at a by-election. Political parties should be allowed to simply nominate replacements when they recall someone.

That is what preserves the right to recall. It also protects the public purse from funding factional fights in political parties.

This is what I refer to as the full meaning of section 129(1)(k). Now, my unpopular view: what of MPs who resign as we are starting to see? Where an MP resigns because they want to join another political party and thus trigger a by-election without being recalled, the clear intention is to defeat the full meaning of section 129(1)(k).

Instead of burdening the public purse with the cost of their transfer to another political party, the party they have left should simply be allowed to appoint a replacement until the next election.
By requiring by-elections each time a person leaves Parliament including to join another political party the Electoral Act removes a Constitutional right belonging to political parties.
Those that understand law without bias will see the reason in this opinion.

Those that think law must bend to what they want will no doubt find comfort in name calling, but any objective person will agree that this is an issue that might benefit from court interpretation.