Grandfathered Annuities

[khn]

We have a 403b plan that has 2 individual annuity contracts that were grandfathered from an older arrangement. The current plan does not offer the annuities as an investment, but the company has been handling the remittance of their contributions.

The plan is converting to another rk so we want to stop this manual process. Are there any formal notification requirements other than telling the 2 participants we won't be remitting the contributions on their behalf anymore?  I can't seem to find anything on this type of situation and would love to hear people's thoughts.