#include<bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); ++i)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
typedef array<int, 3> ai3;
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3fll;
const int Mod = 998244353;
inline int sign(int a){ return (a&1) ? (Mod-1) : 1; }
inline void uadd(int &a, int b){ a += b-Mod; a += (a>>31) & Mod; }
inline void usub(int &a, int b){ a -= b, a += (a>>31) & Mod; }
inline void umul(int &a, int b){ a = (int)(1ll * a * b % Mod); }
inline int add(int a, int b){ a += b-Mod; a += (a>>31) & Mod; return a; }
inline int sub(int a, int b){ a -= b, a += (a>>31) & Mod; return a; }
inline int mul(int a, int b){ a = (int)(1ll * a * b % Mod); return a; }
int qpow(int b, ll p){ int ret = 1; while(p){ if(p&1) umul(ret, b); umul(b, b), p >>= 1; } return ret; }
const int fN = 1010;
int fact[fN], invfact[fN], pw2[fN], invpw2[fN], inv[fN];
void initfact(int n){
	pw2[0] = 1; for(int i = 1; i <= n; ++i) pw2[i] = mul(pw2[i-1], 2);
	invpw2[0] = 1; for(int i = 1; i <= n; ++i) invpw2[i] = mul(invpw2[i-1], (Mod+1) / 2);
	fact[0] = 1; for(int i = 1; i <= n; ++i) fact[i] = mul(fact[i-1], i);
	invfact[n] = qpow(fact[n], Mod-2); for(int i = n; i > 0; --i) invfact[i-1] = mul(invfact[i], i);
	for(int i = 1; i <= n; ++i) inv[i] = mul(invfact[i], fact[i-1]);
}
int binom(int n, int m){ return (m < 0 || m > n) ? 0 : mul(fact[n], mul(invfact[m], invfact[n-m])); }
const double pi = acos(-1);
inline void chmax(int &a, int b){ (b>a) ? (a=b) : 0; }
inline void chmin(int &a, int b){ (b<a) ? (a=b) : 0; }

int n, m;
string s[111];
bool done[111][111];
bool ok = 1;
bool dfs(int x, int y);
bool check(int x, int y){
	if((s[x][y] != '?') + (s[x][y+1] != '?') + (s[x+1][y] != '?') + (s[x+1][y+1] != '?') >= 3){
		if(s[x][y] != s[x][y+1] && s[x][y] == s[x+1][y+1] && s[x+1][y] == s[x][y+1]) return 0;
		//cout << "check " << x << " " << y << "\n";
		if(s[x][y] == s[x+1][y+1]){
			if(s[x+1][y] == '?'){
				if(s[x][y+1] == s[x][y]) return 1;
				else {
					s[x+1][y] = s[x][y];
					return dfs(x+1, y);
				}
			} else {
				if(s[x+1][y] == s[x][y]) return 1;
				else {
					s[x][y+1] = s[x][y];
					return dfs(x, y+1);
				}
			}
		}
		if(s[x][y+1] == s[x+1][y]){
			//cout << " ???\n";
			if(s[x][y] == '?'){
				if(s[x+1][y+1] == s[x+1][y]) return 1;
				else {
					s[x][y] = s[x+1][y];
					return dfs(x, y);
				}
			} else {
				if(s[x][y] == s[x+1][y]) return 1;
				else {
					s[x+1][y+1] = s[x+1][y];
					return dfs(x+1, y+1);
				}
			}
		}
	}
	return 1;
}
bool dfs(int x, int y){
	if(done[x][y]) return 1;
	done[x][y] = 1;
	if(x+1 < n && y+1 < m) if(!check(x, y)) return 0;
	if(x && y+1 < m) if(!check(x-1, y)) return 0;
	if(x+1 < n && y) if(!check(x, y-1)) return 0;
	if(x && y) if(!check(x-1, y-1)) return 0;
	return 1;
}

mt19937 rng(58);
inline int myrand(int l, int r){ return (int)(rng() % (r-l+1)) + l; }
string ans[111];

bool search(int x, int y){
	if(y >= m) ++x, y = 0;
	if(x >= n) return 1;
	auto nxt = [&](){
		if(!(x && y && !(ans[x][y] == ans[x][y-1] || ans[x][y] != ans[x-1][y-1] || ans[x][y-1] != ans[x-1][y]))) if(search(x, y+1)) return 1;
		return 0;
	};
	if(s[x][y] != '?'){
		ans[x][y] = s[x][y];
		return nxt();
	} else {
		ans[x][y] = myrand(0, 1) ? 'W' : 'B';
		if(nxt()) return 1;
		ans[x][y] ^= ('W' ^ 'B');
		if(nxt()) return 1;
		return 0;
	}
}

void solve(){
	cin >> n >> m;
	rep(i, n) cin >> s[i];
	rep(i, n) rep(j, m) done[i][j] = 0;
	ok = 1;
	rep(i, n) rep(j, m) if(s[i][j] != '?' && !done[i][j]) ok &= dfs(i, j);

	//cout << ": \n";
	//rep(i, n) cout << s[i] << "\n";

	if(!ok) cout << "NO\n";
	else {
		cout << "YES\n";
		rep(i, n) ans[i] = s[i];
		search(0, 0);
		rep(i, n) cout << ans[i] << "\n";
	}
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);

	int T;
	cin >> T;
	while(T--) solve();

	return 0;
}