Bhagavad Gita · Dhyana Yoga (Atma-samyama Yoga)Chapter 6, Shloka 30 (6.30)

"Na praṇaśyāmi" — literally "I am not destroyed"; both acharyas read it as not being lost from sight / not becoming remote.

Shankaracharya. Yo māṃ paśyati vāsudevaṃ sarvasya ātmānaṃ sarvatra — one who sees Me, Vasudeva, everywhere as the self of all; ahaṃ īśvaraḥ na praṇaśyāmi na parokṣatāṃ gamiṣyāmi — I, Ishvara, do not become remote for that one; sa ca … na parokṣo bhavati tasya ca mama ca ekātmakatvāt — nor does that one become remote for Me, because we two are one self; svātmā hi nāma ātmanaḥ priya eva bhavati — one's own self is, after all, the dearest of all.

Acharya Ramanuja — the second stage: likeness to the Lord. Tato vipāka-daśām āpanno mama sādharmyam upāgataḥ — in the next stage of ripening, one attains My sādharmya (likeness of nature); evidence, Mundaka 3.1.3: nirañjanaḥ paramaṃ sāmyam upaiti. Such a one vidhūta-puṇya-pāpasya svarūpeṇa avasthitasya mat-sāmyaṃ paśyan — sees likeness to Me in the pure self freed from merit and sin; anyonya-sāmyāt anyatara-darśanena anyatarad api īdṛśam iti paśyati — because of mutual likeness, seeing one, knows the other to be the same. The fruit: ahaṃ … na adarśanam upayāmi — I do not become invisible to that one; nor that one to Me.

The difference: Shankara — "ekātmakatva" (Ishvara and the wise one are one); Ramanuja — "sādharmya / sāmya" (the pure self is like the Lord, but not one with Him).